id Genomic Epidemiology of Complex, Multispecies, Plasmid-Borne blaKPC Carbapenemase in Enterobacterales in the United Kingdom from 2009 to 2014 [Epidemiology and Surveillance] By aac.asm.org Published On :: 2020-04-21T08:01:10-07:00 Carbapenem resistance in Enterobacterales is a public health threat. Klebsiella pneumoniae carbapenemase (encoded by alleles of the blaKPC family) is one of the most common transmissible carbapenem resistance mechanisms worldwide. The dissemination of blaKPC historically has been associated with distinct K. pneumoniae lineages (clonal group 258 [CG258]), a particular plasmid family (pKpQIL), and a composite transposon (Tn4401). In the United Kingdom, blaKPC has represented a large-scale, persistent management challenge for some hospitals, particularly in North West England. The dissemination of blaKPC has evolved to be polyclonal and polyspecies, but the genetic mechanisms underpinning this evolution have not been elucidated in detail; this study used short-read whole-genome sequencing of 604 blaKPC-positive isolates (Illumina) and long-read assembly (PacBio)/polishing (Illumina) of 21 isolates for characterization. We observed the dissemination of blaKPC (predominantly blaKPC-2; 573/604 [95%] isolates) across eight species and more than 100 known sequence types. Although there was some variation at the transposon level (mostly Tn4401a, 584/604 [97%] isolates; predominantly with ATTGA-ATTGA target site duplications, 465/604 [77%] isolates), blaKPC spread appears to have been supported by highly fluid, modular exchange of larger genetic segments among plasmid populations dominated by IncFIB (580/604 isolates), IncFII (545/604 isolates), and IncR (252/604 isolates) replicons. The subset of reconstructed plasmid sequences (21 isolates, 77 plasmids) also highlighted modular exchange among non-blaKPC and blaKPC plasmids and the common presence of multiple replicons within blaKPC plasmid structures (>60%). The substantial genomic plasticity observed has important implications for our understanding of the epidemiology of transmissible carbapenem resistance in Enterobacterales for the implementation of adequate surveillance approaches and for control. Full Article
id The Antifungal Drug Isavuconazole Is both Amebicidal and Cysticidal against Acanthamoeba castellanii [Experimental Therapeutics] By aac.asm.org Published On :: 2020-04-21T08:01:10-07:00 Current treatments for Acanthamoeba keratitis rely on a combination of chlorhexidine gluconate, propamidine isethionate, and polyhexamethylene biguanide. These disinfectants are nonspecific and inherently toxic, which limits their effectiveness. Furthermore, in 10% of cases, recurrent infection ensues due to the difficulty in killing both trophozoites and double-walled cysts. Therefore, development of efficient, safe, and target-specific drugs which are capable of preventing recurrent Acanthamoeba infection is a critical unmet need for averting blindness. Since both trophozoites and cysts contain specific sets of membrane sterols, we hypothesized that antifungal drugs targeting sterol 14-demethylase (CYP51), known as conazoles, would have deleterious effects on A. castellanii trophozoites and cysts. To test this hypothesis, we first performed a systematic screen of the FDA-approved conazoles against A. castellanii trophozoites using a bioluminescence-based viability assay adapted and optimized for Acanthamoeba. The most potent drugs were then evaluated against cysts. Isavuconazole and posaconazole demonstrated low nanomolar potency against trophozoites of three clinical strains of A. castellanii. Furthermore, isavuconazole killed trophozoites within 24 h and suppressed excystment of preformed Acanthamoeba cysts into trophozoites. The rapid action of isavuconazole was also evident from the morphological changes at nanomolar drug concentrations causing rounding of trophozoites within 24 h of exposure. Given that isavuconazole has an excellent safety profile, is well tolerated in humans, and blocks A. castellanii excystation, this opens an opportunity for the cost-effective repurposing of isavuconazole for the treatment of primary and recurring Acanthamoeba keratitis. Full Article
id Hydrogen Peroxide-Mediated Oxygen Enrichment Eradicates Helicobacter pylori In Vitro and In Vivo [Experimental Therapeutics] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Helicobacter pylori is an important risk factor for gastric ulcers. However, antibacterial therapies increase the resistance rate and decrease the eradication rate of H. pylori. Inspired by the microaerophilic characteristics of H. pylori, we aimed at effectively establishing an oxygen-enriched environment to eradicate and prevent the recurrence of H. pylori. The effect and the mechanism of an oxygen-enriched environment in eradicating H. pylori and preventing the recurrence were explored in vitro and in vivo. During oral administration and after drug withdrawal, H. pylori counts were evaluated by Giemsa staining in animal cohorts. An oxygen-enriched environment in which H. pylori could not survive was successfully established by adding hydrogen peroxide into several solutions and rabbit gastric juice. Hydrogen peroxide effectively killed H. pylori in Columbia blood agar and special peptone broth. Minimum inhibition concentrations and minimum bactericidal concentrations of hydrogen peroxide were both relatively stable after promotion of resistance for 30 generations, indicating that hydrogen peroxide did not easily promote resistance in H. pylori. In models of Mongolian gerbils and Kunming mice, hydrogen peroxide has been shown to significantly eradicate and effectively prevent the recurrence of H. pylori without toxicity and damage to the gastric mucosa. The mechanism of hydrogen peroxide causing H. pylori death was related to the disruption of bacterial cell membranes. The oxygen-enriched environment achieved by hydrogen peroxide eradicates and prevents the recurrence of H. pylori by damaging bacterial cell membranes. Hydrogen peroxide thus provides an attractive candidate for anti-H. pylori treatment. Full Article
id Hypermutator Pseudomonas aeruginosa Exploits Multiple Genetic Pathways To Develop Multidrug Resistance during Long-Term Infections in the Airways of Cystic Fibrosis Patients [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Pseudomonas aeruginosa exploits intrinsic and acquired resistance mechanisms to resist almost every antibiotic used in chemotherapy. Antimicrobial resistance in P. aeruginosa isolates recovered from cystic fibrosis (CF) patients is further enhanced by the occurrence of hypermutator strains, a hallmark of chronic infections in CF patients. However, the within-patient genetic diversity of P. aeruginosa populations related to antibiotic resistance remains unexplored. Here, we show the evolution of the mutational resistome profile of a P. aeruginosa hypermutator lineage by performing longitudinal and transversal analyses of isolates collected from a CF patient throughout 20 years of chronic infection. Our results show the accumulation of thousands of mutations, with an overall evolutionary history characterized by purifying selection. However, mutations in antibiotic resistance genes appear to have been positively selected, driven by antibiotic treatment. Antibiotic resistance increased as infection progressed toward the establishment of a population constituted by genotypically diversified coexisting sublineages, all of which converged to multidrug resistance. These sublineages emerged by parallel evolution through distinct evolutionary pathways, which affected genes of the same functional categories. Interestingly, ampC and ftsI, encoding the β-lactamase and penicillin-binding protein 3, respectively, were found to be among the most frequently mutated genes. In fact, both genes were targeted by multiple independent mutational events, which led to a wide diversity of coexisting alleles underlying β-lactam resistance. Our findings indicate that hypermutators, apart from boosting antibiotic resistance evolution by simultaneously targeting several genes, favor the emergence of adaptive innovative alleles by clustering beneficial/compensatory mutations in the same gene, hence expanding P. aeruginosa strategies for persistence. Full Article
id Multiple Copies of blaNDM-5 Located on Conjugative Megaplasmids from Porcine Escherichia coli Sequence Type 218 Isolates [Letters] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Full Article
id Effects of Tenofovir on the Single-Dose Pharmacokinetics of Intravenous Morinidazole in Healthy Chinese Subjects [Pharmacology] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 The effects of multiple-dose administration of tenofovir disoproxil fumarate (TDF) on the pharmacokinetics of morinidazole (MOR) were compared in healthy subjects. MOR exposure was similar, with an area under the curve from 0 h to infinity (AUC0-) treatment ratio for MOR+TDF/MOR of 1.01 (90% confidence interval, 0.97 to 1.06). No relevant differences were observed regarding plasma exposure of metabolites. Renal clearances of MOR and its metabolites were not affected by TDF. No unexpected safety or tolerability issues were observed. Full Article
id Comparison of Commensal and Clinical Isolates for Diversity of Plasmids in Escherichia coli and Klebsiella pneumoniae [Epidemiology and Surveillance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 In this study, the plasmid content of clinical and commensal strains was analyzed and compared. The replicon profile was similar in both populations, except for L, M, A/C, and N (detected only in clinical strains) and HI1 (only in commensal strains). Although I1 and F were the most frequent replicons, only IncI1, sequence type 12 (ST12) was associated with blaCMY-2 in both populations. In contrast, the widespread resistant IncF plasmids were not linked to a single epidemic plasmid. Full Article
id Novel Insights into Plasmodium vivax Therapeutic Failure: CYP2D6 Activity and Time of Exposure to Malaria Modulate the Risk of Recurrence [Epidemiology and Surveillance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Plasmodium vivax relapse is one of the major causes of sustained global malaria transmission. Primaquine (PQ) is the only commercial drug available to prevent relapses, and its efficacy is dependent on metabolic activation by cytochrome P450 2D6 (CYP2D6). Impaired CYP2D6 function, caused by allelic polymorphisms, leads to the therapeutic failure of PQ as a radical cure for P. vivax malaria. Here, we hypothesized that the host immune response to malaria parasites modulates susceptibility to P. vivax recurrences in association with CYP2D6 activity. We performed a 10-year retrospective study by genotyping CYP2D6 polymorphisms in 261 malaria-exposed individuals from the Brazilian Amazon. The immune responses against a panel of P. vivax blood-stage antigens were evaluated by serological assays. We confirmed our previous findings, which indicated an association between impaired CYP2D6 activity and a higher risk of multiple episodes of P. vivax recurrence (risk ratio, 1.75; 95% confidence interval [CI], 1.2 to 2.6; P = 0.0035). An important finding was a reduction of 3% in the risk of recurrence (risk ratio, 0.97; 95% CI, 0.96 to 0.98; P < 0.0001) per year of malaria exposure, which was observed for individuals with both reduced and normal CYP2D6 activity. Accordingly, subjects with long-term malaria exposure and persistent antibody responses to various antigens showed fewer episodes of malaria recurrence. Our findings have direct implications for malaria control, since it was shown that nonimmune individuals who do not respond adequately to treatment due to reduced CYP2D6 activity may present a significant challenge for sustainable progress toward P. vivax malaria elimination. Full Article
id Early Bactericidal Activity Trial of Nitazoxanide for Pulmonary Tuberculosis [Clinical Therapeutics] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 This study was conducted in treatment-naive adults with drug-susceptible pulmonary tuberculosis in Port-au-Prince, Haiti, to assess the safety, bactericidal activity, and pharmacokinetics of nitazoxanide (NTZ). This was a prospective phase II clinical trial in 30 adults with pulmonary tuberculosis. Twenty participants received 1 g of NTZ orally twice daily for 14 days. A control group of 10 participants received standard therapy over 14 days. The primary outcome was the change in time to culture positivity (TTP) in an automated liquid culture system. The most common adverse events seen in the NTZ group were gastrointestinal complaints and headache. The mean change in TTP in sputum over 14 days in the NTZ group was 3.2 h ± 22.6 h and was not statistically significant (P = 0.56). The mean change in TTP in the standard therapy group was significantly increased, at 134 h ± 45.2 h (P < 0.0001). The mean NTZ MIC for Mycobacterium tuberculosis isolates was 12.3 μg/ml; the mean NTZ maximum concentration (Cmax) in plasma was 10.2 μg/ml. Negligible NTZ levels were measured in sputum. At the doses used, NTZ did not show bactericidal activity against M. tuberculosis. Plasma concentrations of NTZ were below the MIC, and its negligible accumulation in pulmonary sites may explain the lack of bactericidal activity. (This study has been registered at ClinicalTrials.gov under identifier NCT02684240.) Full Article
id Activity of Cefiderocol and Comparators against Isolates from Cancer Patients [Susceptibility] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Cefiderocol inhibited 97.5% of 478 Gram-negative isolates from cancer patients at ≤4 mg/liter. It had potent activity against extended-spectrum β-lactamase-positive Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae (CRE), and nonfermenting Gram-negative bacilli, including Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter species isolates. Amikacin, ceftazidime-avibactam, and meropenem had appreciable activity against non-CRE Enterobacteriaceae. No comparators were active against multidrug-resistant P. aeruginosa isolates. Only trimethoprim-sulfamethoxazole had appreciable activity against S. maltophilia isolates. Overall, cefiderocol was associated with the lowest level of resistance. Full Article
id Whole-Cell Phenotypic Screening of Medicines for Malaria Venture Pathogen Box Identifies Specific Inhibitors of Plasmodium falciparum Late-Stage Development and Egress [Experimental Therapeutics] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 We report a systematic, cellular phenotype-based antimalarial screening of the Medicines for Malaria Venture Pathogen Box collection, which facilitated the identification of specific blockers of late-stage intraerythrocytic development of Plasmodium falciparum. First, from standard growth inhibition assays, we identified 173 molecules with antimalarial activity (50% effective concentration [EC50] ≤ 10 μM), which included 62 additional molecules over previously known antimalarial candidates from the Pathogen Box. We identified 90 molecules with EC50 of ≤1 μM, which had significant effect on the ring-trophozoite transition, while 9 molecules inhibited the trophozoite-schizont transition and 21 molecules inhibited the schizont-ring transition (with ≥50% parasites failing to proceed to the next stage) at 1 μM. We therefore rescreened all 173 molecules and validated hits in microscopy to prioritize 12 hits as selective blockers of the schizont-ring transition. Seven of these molecules inhibited the calcium ionophore-induced egress of Toxoplasma gondii, a related apicomplexan parasite, suggesting that the inhibitors may be acting via a conserved mechanism which could be further exploited for target identification studies. We demonstrate that two molecules, MMV020670 and MMV026356, identified as schizont inhibitors in our screens, induce the fragmentation of DNA in merozoites, thereby impairing their ability to egress and invade. Further mechanistic studies would facilitate the therapeutic exploitation of these molecules as broadly active inhibitors targeting late-stage development and egress of apicomplexan parasites relevant to human health. Full Article
id Adduct Formation of Delamanid with NAD in Mycobacteria [Mechanisms of Action] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Delamanid (DLM), a nitro-dihydroimidazooxazole derivative currently approved for pulmonary multidrug-resistant tuberculosis (TB) therapy, is a prodrug activated by mycobacterial 7,8-didemethyl-8-hydroxy 5-deazaflavin electron transfer coenzyme (F420)-dependent nitroreductase (Ddn). Despite inhibiting the biosynthesis of a subclass of mycolic acids, the active DLM metabolite remained unknown. Comparative liquid chromatography-mass spectrometry (LC-MS) analysis of DLM metabolites revealed covalent binding of reduced DLM with a nicotinamide ring of NAD derivatives (oxidized form) in DLM-treated Mycobacterium tuberculosis var. Bacille de Calmette et Guérin. Isoniazid-resistant mutations in the type II NADH dehydrogenase gene (ndh) showed a higher intracellular NADH/NAD ratio and cross-resistance to DLM, which were restored by complementation of the mutants with wild-type ndh. Our data demonstrated for the first time the adduct formation of reduced DLM with NAD in mycobacterial cells and its importance in the action of DLM. Full Article
id Distinct Mechanisms of Dissemination of NDM-1 Metallo-{beta}-Lactamase in Acinetobacter Species in Argentina [Epidemiology and Surveillance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 A 4-year surveillance of carbapenem-resistant Acinetobacter spp. isolates in Argentina identified 40 strains carrying blaNDM-1. Genome sequencing revealed that most were Acinetobacter baumannii, whereas seven represented other Acinetobacter spp. The A. baumannii genomes were closely related, suggesting recent spread. blaNDM-1 was located in the chromosome of A. baumannii strains and on a plasmid in non-A. baumannii strains. A resistance gene island carrying blaPER-7 and other resistance determinants was found on a plasmid in some A. baumannii strains. Full Article
id Whole-Genome Characterization of a Shewanella algae Strain Coharboring blaCTX-M-15 and armA Genes on a Novel IncC Plasmid [Letters] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Full Article
id Enhanced Efflux Pump Expression in Candida Mutants Results in Decreased Manogepix Susceptibility [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Manogepix is a broad-spectrum antifungal agent that inhibits glycosylphosphatidylinositol (GPI) anchor biosynthesis. Using whole-genome sequencing, we characterized two efflux-mediated mechanisms in the fungal pathogens Candida albicans and Candida parapsilosis that resulted in decreased manogepix susceptibility. In C. albicans, a gain-of-function mutation in the transcription factor gene ZCF29 activated expression of ATP-binding cassette transporter genes CDR11 and SNQ2. In C. parapsilosis, a mitochondrial deletion activated expression of the major facilitator superfamily transporter gene MDR1. Full Article
id Characterization of blaCTX-M-27/F1:A2:B20 Plasmids Harbored by Escherichia coli Sequence Type 131 Sublineage C1/H30R Isolates Spreading among Elderly Japanese in Nonacute-Care Settings [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 We characterized 29 blaCTX-M-27-harboring plasmids of Escherichia coli sequence type 131 (ST131) sublineage C1/H30R isolates from healthy individuals and long-term-care facility (LTCF) residents. Most (27/29) plasmids were of the FIA, FIB, and FII multireplicon type with the same plasmid multilocus sequence typing (pMLST). Several plasmids (7/23) from LTCF residents harbored only blaCTX-M-27 as the resistance gene; however, their fundamental structures were very similar to those of previously isolated blaCTX-M-27/F1:A2:B20 plasmids, suggesting their prevalence as a newly arising public health concern. Full Article
id Molecular and Clinical Characterization of Multidrug-Resistant and Hypervirulent Klebsiella pneumoniae Strains from Liver Abscess in Taiwan [Epidemiology and Surveillance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Hypervirulent Klebsiella pneumoniae strains are the major cause of liver abscesses throughout East Asia, and these strains are usually antibiotic susceptible. Recently, multidrug-resistant and hypervirulent (MDR-HV) K. pneumoniae strains have emerged due to hypervirulent strains acquiring antimicrobial resistance determinants or the transfer of a virulence plasmid into a classic MDR strain. In this study, we characterized the clinical and microbiological properties of K. pneumoniae liver abscess (KPLA) caused by MDR-HV strains in Taiwan. Patients with community onset KPLA were retrospectively identified at Taipei Veterans General Hospital during January 2013 to May 2018. Antimicrobial resistance mechanisms, capsular types, and sequence types were determined. MDR-HV strains and their parental antimicrobial-susceptible strains further underwent whole-genome sequencing (WGS) and in vivo mice lethality tests. Thirteen MDR-HV strains were identified from a total of 218 KPLA episodes. MDR-HV strains resulted in similar outcomes to antimicrobial-susceptible strains. All MDR-HV strains were traditional hypervirulent clones carrying virulence capsular types. The major resistance mechanisms were the overexpression of efflux pumps and/or the acquisition of ESBL or AmpC β-lactamase genes. WGS revealed that two hypervirulent strains had evolved to an MDR phenotype due to mutation in the ramR gene and the acquisition of an SHV-12-bearing plasmid, respectively. Both these MDR-HV strains retained high virulence compared to their parental strains. The spread of MDR-HV K. pneumoniae strains in the community raises significant public concerns, and measures should be taken to prevent the further acquisition of carbapenemase and other resistance genes among these strains in order to avoid the occurrence of untreatable KPLA. Full Article
id The Novel Macrolide Resistance Genes mef(D), msr(F), and msr(H) Are Present on Resistance Islands in Macrococcus canis, Macrococcus caseolyticus, and Staphylococcus aureus [Mechanisms of Resistance] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Chromosomal resistance islands containing the methicillin resistance gene mecD (McRImecD) have been reported in Macrococcus caseolyticus. Here, we identified novel macrolide resistance genes in Macrococcus canis on similar elements, called McRImsr. These elements were also integrated into the 3' end of the 30S ribosomal protein S9 gene (rpsI), delimited by characteristic attachment (att) sites, and carried a related site-specific integrase gene (int) at the 5' end. They carried novel macrolide resistance genes belonging to the msr family of ABC subfamily F (ABC-F)-type ribosomal protection protein [msr(F) and msr(H)] and the macrolide efflux mef family [mef(D)]. Highly related mef(D)-msr(F) fragments were found on diverse McRImsr elements in M. canis, M. caseolyticus, and Staphylococcus aureus. Another McRImsr-like element identified in an M. canis strain lacked the classical att site at the 3' end and carried the msr(H) gene but no neighboring mef gene. The expression of the novel resistance genes in S. aureus resulted in a low-to-moderate increase in the MIC of erythromycin but not streptogramin B. In the mef(D)-msr(F) operon, the msr(F) gene was shown to be the crucial determinant for macrolide resistance. The detection of circular forms of McRImsr and the mef(D)-msr(F) fragment suggested mobility of both the island and the resistance gene subunit. The discovery of McRImsr in different Macrococcus species and S. aureus indicates that these islands have a potential for dissemination of antibiotic resistance within the Staphylococcaceae family. Full Article
id Levonadifloxacin, a Novel Benzoquinolizine Fluoroquinolone, Modulates Lipopolysaccharide-Induced Inflammatory Responses in Human Whole-Blood Assay and Murine Acute Lung Injury Model [Pharmacology] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 Fluoroquinolones are reported to possess immunomodulatory activity; hence, a novel benzoquinolizine fluoroquinolone, levonadifloxacin, was evaluated in lipopolysaccharide-stimulated human whole-blood (HWB) and mouse acute lung injury (ALI) models. Levonadifloxacin significantly mitigated the inflammatory responses in an HWB assay through inhibition of proinflammatory cytokines and in the ALI model by lowering lung total white blood cell count, myeloperoxidase, and cytokine levels. The immunomodulatory effect of levonadifloxacin, along with promising antibacterial activity, is expected to provide clinical benefits in the treatment of infections. Full Article
id Accumulation of Major Linezolid Metabolites in Patients with Renal Impairment [Pharmacology] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 In patients with renal impairment (n = 22 of 39), the median serum concentrations of linezolid, PNU-142300, and PNU-142586 were 1.6-, 3.3-, 2.8-fold higher, respectively, than in patients without renal impairment. Metabolite concentrations in paired samples were poorly correlated with linezolid concentrations (r2 = 0.26 for PNU-142300 and 0.06 for PNU-142586). Linezolid and its metabolites share potential toxicophores that deserve characterization to mitigate higher myelosuppression risk in patients with renal impairment. Full Article
id Insecticidal Activity of Doxycycline against the Common Bedbug [Experimental Therapeutics] By aac.asm.org Published On :: 2020-04-21T08:01:09-07:00 There is an ongoing need for safe and effective anti-bedbug compounds. Here, we tested the toxicity of three antimicrobial agents against bedbugs when administered orally. We reveal that doxycycline has direct insecticidal activity at 250 μg/ml (0.025%) that is particularly strong against immature bedbugs and appears to be independent of antimicrobial activity. Future studies to determine the mechanisms behind this property could be useful for the development of orally active insecticides or anti-bedbug therapeutics. Full Article
id Targeting HER2 with Trastuzumab Deruxtecan: A Dose-Expansion, Phase I Study in Multiple Advanced Solid Tumors [Research Articles] By cancerdiscovery.aacrjournals.org Published On :: 2020-05-01T00:05:26-07:00 HER2-targeted therapies are approved only for HER2-positive breast and gastric cancers. We assessed the safety/tolerability and activity of the novel HER2-targeted antibody–drug conjugate trastuzumab deruxtecan (T-DXd) in 60 patients with pretreated, HER2-expressing (IHC ≥ 1+), non-breast/non-gastric or HER2-mutant solid tumors from a phase I trial (NCT02564900). Most common (>50%) treatment-emergent adverse events (TEAE) were nausea, decreased appetite, and vomiting. Two drug-related TEAEs were associated with fatal outcomes. The confirmed objective response rate (ORR) was 28.3% (17/60). Median progression-free survival (PFS) was 7.2 [95% confidence interval (CI), 4.8–11.1] months. In HER2-mutant non–small cell lung cancer (NSCLC), ORR was 72.7% (8/11), and median PFS was 11.3 (95% CI, 8.1–14.3) months. Confirmed responses were observed in six tumor types, including HER2-expressing NSCLC, colorectal cancer, salivary gland cancer, biliary tract cancer, endometrial cancer, and HER2-mutant NSCLC and breast cancer. Results suggest T-DXd holds promise for HER2-expressing/mutant solid tumors. Significance: T-DXd demonstrated promising activity in a heterogeneous patient population with heavily pretreated HER2-expressing or HER2-mutant solid tumors, especially HER2-mutant NSCLC. The safety profile was generally acceptable. Interstitial lung disease can be severe and requires prompt monitoring and intervention. Further research of T-DXd is warranted to address these unmet medical needs. See related commentary by Rolfo and Russo, p. 643. This article is highlighted in the In This Issue feature, p. 627 Full Article
id New Drug-Discovery Assay Identifies Novel Mutant-EGFR Inhibitors [Drug Discovery] By cancerdiscovery.aacrjournals.org Published On :: 2020-05-01T00:05:26-07:00 The MaMTH-DS assay detected inhibitors of mutant EGFR in non–small cell lung cancer cells. Full Article
id Cancer Labs Pivot to Battle COVID-19 [News in Depth] By cancerdiscovery.aacrjournals.org Published On :: 2020-05-01T00:05:26-07:00 As cancer researchers shutter their labs to comply with COVID-19–related work restrictions, some are turning their attention, resources, and technical know-how to the challenge of tackling the deadly coronavirus. Full Article
id Clinical Research Slows as COVID-19 Surges [News in Brief] By cancerdiscovery.aacrjournals.org Published On :: 2020-05-01T00:05:26-07:00 As the COVID-19 pandemic worsens, the clinical cancer community is grappling with how to continue providing access to experimental but potentially lifesaving therapies while keeping immunocompromised patients safe. To that end, cancer centers are making changes to their clinical trial programs, while pharmaceutical companies are deciding how—or whether—trials should continue. Full Article
id Ubiquitination Causes Fanconi Anemia-Linked ID Complex Ring Formation [Structural Biology] By cancerdiscovery.aacrjournals.org Published On :: 2020-05-01T00:05:26-07:00 Monoubiquitinated FANCI and FANCD2 constitute the ID complex, which forms a sliding clamp on DNA. Full Article
id Retinoic Acid Mediates Monocyte Differentiation and Immune Response [Immunology] By cancerdiscovery.aacrjournals.org Published On :: 2020-05-01T00:05:26-07:00 Tumor-derived retinoic acid promotes monocyte differentiation into immunosuppressive macrophages. Full Article
id COVID-19 Challenges Basic Researchers [News in Brief] By cancerdiscovery.aacrjournals.org Published On :: 2020-05-01T00:05:26-07:00 As COVID-19 continues to surge, cancer scientists engaged in basic research face unique challenges. At centers throughout the United States, investigators are confronting difficult decisions about which experiments to continue, while securing supplies and creating contingency plans for a complete shutdown. Full Article
id The diagnostic challenges and clinical course of a myeloid/lymphoid neoplasm with eosinophilia and ZBTB20-JAK2 gene fusion presenting as B-lymphoblastic leukemia [RESEARCH REPORT] By molecularcasestudies.cshlp.org Published On :: 2020-04-01T06:30:17-07:00 We report the diagnostic challenges and the clinical course of a patient with an extraordinary presentation of B-lymphoblastic leukemia (B-ALL) with eosinophilia. We identified a novel ZBTB20-JAK2 gene fusion as a chimeric RNA transcript using the Archer platform. This gene fusion from the same patient was recently identified by Peterson et al. (2019) at the genomic level using a different sequencing technology platform. The configuration of this gene fusion predicts the production of a kinase-activating JAK2 fusion protein, which would normally lead to a diagnosis of Philadelphia chromosome–like B-ALL (Ph-like B-ALL). However, the unusual presentation of eosinophilia led us to demonstrate the presence of this gene fusion in nonlymphoid hematopoietic cells by fluorescence in situ hybridization (FISH) studies with morphologic correlation. Therefore, we believe this disease, in fact, represents blast crisis arising from an underlying myeloid neoplasm with JAK2 rearrangements. This case illustrates the difficulty in differentiating Ph-like B-ALL and myeloid/lymphoid neoplasm with eosinophilia and gene rearrangements (MLN-EGR) in blast crisis. As currently defined, the diagnosis of MLN-EGR relies on the hematologic presentations and the identification of marker gene fusions (including PCM1-JAK2, ETV6-JAK2, and BCR-JAK2). However, these same gene fusions, when limited to B-lymphoblasts, also define Ph-like B-ALL. Yet, our case does not conform to either condition. Therefore, the assessment for lineage restriction of gene rearrangements to reflect the pathophysiologic difference between B-ALL and MLN-EGR in blast crisis is likely a more robust diagnostic approach and allows the inclusion of MLN-EGR with novel gene fusions. Full Article
id Erratum. Diabetes Is Primary: Timely News and Notes for Primary Care Providers. Clinical Diabetes 2020;38:4-8 (DOI: 10.2337/cd20-dp01) By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 Full Article
id A Case of Euglycemic Diabetic Ketoacidosis Triggered by a Ketogenic Diet in a Patient With Type 2 Diabetes Using a Sodium-Glucose Cotransporter 2 Inhibitor By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 Full Article
id Good to Know: Kidney Disease: Signs and Treatment By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 Full Article
id Cleveland Clinic Foundation Internal Medicine Residency Program By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 Quality Improvement Success Stories are published by the American Diabetes Association in collaboration with the American College of Physicians, Inc. (ACP), and the National Diabetes Education Program. This series is intended to highlight best practices and strategies from programs and clinics that have successfully improved the quality of care for people with diabetes or related conditions. Each article in the series is reviewed and follows a standard format developed by the editors of Clinical Diabetes. The following article describes an initiative of the Cleveland Clinic’s internal medicine residents to improve diabetes care and outcomes within an underserved patient population at an East Cleveland, OH, health center. Full Article
id Distribution of Highly Prevalent Musculoskeletal Disorders and Their Association With Diabetes Complications in a Population of 140 Individuals With Type 1 Diabetes: A Retrospective Study in a French Diabetes Center By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 Although they are usually not considered to be diabetes complications, musculoskeletal disorders (MSKDs) are common in individuals with type 1 or type 2 diabetes and can strongly interfere with daily diabetes care, especially in people using diabetes technologies. The authors of this retrospective study in a population of 140 patients with type 1 diabetes report the distribution of subtypes of MSKDs and speculate about the mechanisms involved. The authors emphasize the need for multidisciplinary care involving not only the diabetes care team but also orthopedic surgeons. This report should lead to large, prospective studies to increase knowledge about these under-studied complications. Full Article
id Beneficial Agents for Patients With Type 2 Diabetes and Cardiovascular Disease or Obesity: Utilization in an Era of Accumulating Evidence By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 This study was an analysis of a national sample of U.S. medical office visits from 2014 to 2016, a period when evidence of effectiveness was emerging for a variety of beneficial type 2 diabetes agents with regard to potential reduction in diabetes comorbidities. Ideal therapy was defined as an American Diabetes Association–identified beneficial agent plus metformin. The associations between atherosclerotic cardiovascular disease or obesity and use of these agents were explored. Full Article
id Primary Care Providers in California and Florida Report Low Confidence in Providing Type 1 Diabetes Care By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 People with type 1 diabetes may receive a significant portion of their care from primary care providers (PCPs). To understand the involvement of PCPs in delivering type 1 diabetes care, we performed surveys in California and Florida, two of the most populous and diverse states in the United States. PCPs fill insulin prescriptions but report low confidence in providing type 1 diabetes care and difficulty accessing specialty referrals to endocrinologists. Full Article
id Diabetic Kidney Disease: It Don’t Get No Respect By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 Full Article
id Timely News and Notes for Primary Care Providers from the American Diabetes Association By clinical.diabetesjournals.org Published On :: 2020-04-15T12:00:21-07:00 Full Article
id Lipid Trait Variants and the Risk of Non-Hodgkin Lymphoma Subtypes: A Mendelian Randomization Study By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 Background: Lipid traits have been inconsistently linked to risk of non-Hodgkin lymphoma (NHL). We examined the association of genetically predicted lipid traits with risk of diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), and marginal zone lymphoma (MZL) using Mendelian randomization (MR) analysis. Methods: Genome-wide association study data from the InterLymph Consortium were available for 2,661 DLBCLs, 2,179 CLLs, 2,142 FLs, 824 MZLs, and 6,221 controls. SNPs associated (P < 5 x 10–8) with high-density lipoprotein (HDL, n = 164), low-density lipoprotein (LDL, n = 137), total cholesterol (TC, n = 161), and triglycerides (TG, n = 123) were used as instrumental variables (IV), explaining 14.6%, 27.7%, 16.8%, and 12.8% of phenotypic variation, respectively. Associations between each lipid trait and NHL subtype were calculated using the MR inverse variance–weighted method, estimating odds ratios (OR) per standard deviation and 95% confidence intervals (CI). Results: HDL was positively associated with DLBCL (OR = 1.14; 95% CI, 1.00–1.30) and MZL (OR = 1.09; 95% CI, 1.01–1.18), while TG was inversely associated with MZL risk (OR = 0.90; 95% CI, 0.83–0.99), all at nominal significance (P < 0.05). A positive trend was observed for HDL with FL risk (OR = 1.08; 95% CI, 0.99–1.19; P = 0.087). No associations were noteworthy after adjusting for multiple testing. Conclusions: We did not find evidence of a clear or strong association of these lipid traits with the most common NHL subtypes. While these IVs have been previously linked to other cancers, our findings do not support any causal associations with these NHL subtypes. Impact: Our results suggest that prior reported inverse associations of lipid traits are not likely to be causal and could represent reverse causality or confounding. Full Article
id Prediagnostic Circulating Levels of Sex Steroid Hormones and SHBG in Relation to Risk of Ductal Carcinoma In Situ of the Breast among UK Women By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 Background: Sex steroid hormones and sex hormone–binding globulin (SHBG) have been implicated in the etiology of invasive breast cancer, but their associations with risk of the precursor lesion, ductal carcinoma in situ (DCIS) of the breast, remain unclear. Methods: We used Cox proportional hazards regression models to estimate the associations of serum levels of estradiol (premenopausal women only), testosterone, and/or SHBG with DCIS risk among 182,935 women. After a median follow-up of 7.1 years, 186 and 531 DCIS cases were ascertained in premenopausal and postmenopausal women, respectively. Results: Total and free estradiol were positively associated with risk of DCIS among premenopausal women. The HRs for the highest versus the lowest tertiles were 1.54 (1.06–2.23) and 1.72 [95% confidence interval (CI), 1.15–2.57], respectively. Among postmenopausal women, elevated levels of free testosterone (FT), and to a lesser extent, total testosterone, were positively associated with DCIS risk. The HRs for the highest versus the lowest quartiles were 1.42 (95% CI, 1.09–1.85) and 1.16 (95% CI, 0.91–1.48), respectively. Serum SHBG levels were inversely associated with risk of DCIS among postmenopausal women (HRq4 vs. q1: 0.75; 95% CI, 0.56–0.99). Conclusions: This study suggests that elevated levels of estradiol are associated with increased risk of DCIS among premenopausal women, and that among postmenopausal women, elevated levels of testosterone, and particularly those of FT, are associated with increased DCIS risk, while elevated levels of SHBG are associated with reduced risk. Impact: These findings may be helpful in developing prevention strategies aimed at reducing breast cancer risk among premenopausal and postmenopausal women. Full Article
id Total Antioxidant Capacity and Pancreatic Cancer Incidence and Mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 Background: Total antioxidant capacity (TAC) reflects an individual's overall antioxidant intake. We sought to clarify whether higher TAC is associated with lower risks of pancreatic cancer incidence and mortality in the U.S. general population. Methods: A total of 96,018 American adults were identified from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. A ferric-reducing ability of plasma score was used to reflect an individual's TAC intake from diet and/or supplements. Cox regression was used to calculate hazard ratios (HR) for pancreatic cancer incidence, and competing risk regression was used to calculate subdistribution HRs for pancreatic cancer mortality. Restricted cubic spline regression was used to test nonlinearity. Results: A total of 393 pancreatic cancer cases and 353 pancreatic cancer–related deaths were documented. Total (diet + supplements) TAC was found to be inversely associated with pancreatic cancer incidence (HR quartile 4 vs. quartile 1 = 0.53; 95% confidence interval, 0.39–0.72; Ptrend = 0.0002) and mortality (subdistribution HR quartile 4 vs. quartile 1 = 0.52; 95% confidence interval 0.38–0.72; Ptrend = 0.0003) in a nonlinear dose–response manner (all Pnonlinearity < 0.01). Similar results were observed for dietary TAC. No association of supplemental TAC with pancreatic cancer incidence and mortality was found. Conclusions: In the U.S. general population, dietary but not supplemental TAC level is inversely associated with risks of pancreatic cancer incidence and mortality in a nonlinear dose–response pattern. Impact: This is the first prospective study indicating that a diet rich in antioxidants may be beneficial in decreasing pancreatic cancer incidence and mortality. Full Article
id Circulating Biomarker Score for Visceral Fat and Risks of Incident Colorectal and Postmenopausal Breast Cancer: The Multiethnic Cohort Adiposity Phenotype Study By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 Background: Visceral adipose tissue (VAT) may play a greater role than subcutaneous fat in increasing cancer risk but is poorly estimated in epidemiologic studies. Methods: We developed a VAT prediction score by regression equations averaged across 100 least absolute shrinkage and selection operator models in a cross-sectional study of 1,801 older adults in the Multiethnic Cohort (MEC). The score was then used as proxy for VAT in case–control studies of postmenopausal breast (950 case–control pairs) and colorectal (831 case–control pairs) cancer in an independent sample in MEC. Abdominal MRI–derived VAT; circulating biomarkers of metabolic, hormonal, and inflammation dysfunctions; and ORs for incident cancer adjusted for BMI and other risk factors were assessed. Results: The final score, composed of nine biomarkers, BMI, and height, explained 11% and 15% more of the variance in VAT than BMI alone in men and women, respectively. The area under the receiver operator curve for VAT >150 cm2 was 0.90 in men and 0.86 in women. The VAT score was associated with risk of breast cancer [OR (95% confidence interval [CI]) by increasing tertiles: 1.00, 1.09 (0.86–1.39), 1.48 (1.16–1.89); Ptrend = 0.002] but not with colorectal cancer (P = 0.84), although an association [1.00, 0.98 (0.68–1.39), 1.24 (0.88–1.76); Ptrend = 0.08] was suggested for this cancer after excluding cases that occurred within 7 years of blood draw (Pheterogeneity = 0.06). Conclusions: The VAT score predicted risks of postmenopausal breast cancer and can be used for risk assessment in diverse populations. Impact: These findings provide specific evidence for a role of VAT in breast cancer. Full Article
id Li-Fraumeni Exploration Consortium Data Coordinating Center: Building an Interactive Web-Based Resource for Collaborative International Cancer Epidemiology Research for a Rare Condition By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 Background: The success of multisite collaborative research relies on effective data collection, harmonization, and aggregation strategies. Data Coordination Centers (DCC) serve to facilitate the implementation of these strategies. The utility of a DCC can be particularly relevant for research on rare diseases where collaboration from multiple sites to amass large aggregate datasets is essential. However, approaches to building a DCC have been scarcely documented. Methods: The Li-Fraumeni Exploration (LiFE) Consortium's DCC was created using multiple open source packages, including LAM/G Application (Linux, Apache, MySQL, Grails), Extraction-Transformation-Loading (ETL) Pentaho Data Integration Tool, and the Saiku-Mondrian client. This document serves as a resource for building a rare disease DCC for multi-institutional collaborative research. Results: The primary scientific and technological objective to create an online central repository into which data from all participating sites could be deposited, harmonized, aggregated, disseminated, and analyzed was completed. The cohort now include 2,193 participants from six contributing sites, including 1,354 individuals from families with a pathogenic or likely variant in TP53. Data on cancer diagnoses are also available. Challenges and lessons learned are summarized. Conclusions: The methods leveraged mitigate challenges associated with successfully developing a DCC's technical infrastructure, data harmonization efforts, communications, and software development and applications. Impact: These methods can serve as a framework in establishing other collaborative research efforts. Data from the consortium will serve as a great resource for collaborative research to improve knowledge on, and the ability to care for, individuals and families with Li-Fraumeni syndrome. Full Article
id Harnessing Population Pedigree Data and Machine Learning Methods to Identify Patterns of Familial Bladder Cancer Risk By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 Background: Relatives of patients with bladder cancer have been shown to be at increased risk for kidney, lung, thyroid, and cervical cancer after correcting for smoking-related behaviors that may concentrate in some families. We demonstrate a novel approach to simultaneously assess risks for multiple cancers to identify distinct multicancer configurations (multiple different cancer types that cluster in relatives) surrounding patients with familial bladder cancer. Methods: This study takes advantage of a unique population-level data resource, the Utah Population Database (UPDB), containing vast genealogy and statewide cancer data. Familial risk is measured using standardized incidence risk (SIR) ratios that account for sex, age, birth cohort, and person-years of the pedigree members. Results: We identify 1,023 families with a significantly higher bladder cancer rate than population controls (familial bladder cancer). Familial SIRs are then calculated across 25 cancer types, and a weighted Gower distance with K-medoids clustering is used to identify familial multicancer configurations (FMC). We found five FMCs, each exhibiting a different pattern of cancer aggregation. Of the 25 cancer types studied, kidney and prostate cancers were most commonly enriched in the familial bladder cancer clusters. Laryngeal, lung, stomach, acute lymphocytic leukemia, Hodgkin disease, soft-tissue carcinoma, esophageal, breast, lung, uterine, thyroid, and melanoma cancers were the other cancer types with increased incidence in familial bladder cancer families. Conclusions: This study identified five familial bladder cancer FMCs showing unique risk patterns for cancers of other organs, suggesting phenotypic heterogeneity familial bladder cancer. Impact: FMC configurations could permit better definitions of cancer phenotypes (subtypes or multicancer) for gene discovery and environmental risk factor studies. Full Article
id One Size Does Not Fit All: Marked Heterogeneity in Incidence of and Survival from Gastric Cancer among Asian American Subgroups By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 Background: Asian Americans are at higher risk for noncardia gastric cancers (NCGC) relative to non-Hispanic Whites (NHW). Asian Americans are genetically, linguistically, and culturally heterogeneous, yet have mostly been treated as a single population in prior studies. This aggregation may obscure important subgroup-specific cancer patterns. Methods: We utilized data from 13 regional United States cancer registries from 1990 to 2014 to determine secular trends in incidence and survivorship from NCGC. Data were analyzed for NHWs and the six largest Asian American subgroups: Chinese, Japanese, Filipino, Korean, Vietnamese, and South Asian (Indian/Pakistani). Results: There exists substantial heterogeneity in NCGC incidence between Asian subgroups, with Koreans (48.6 per 100,000 person-years) having seven-fold higher age-adjusted incidence than South Asians (7.4 per 100,000 person-years). Asians had generally earlier stages of diagnosis and higher rates of surgical resection compared with NHWs. All Asian subgroups also demonstrated higher 5-year observed survival compared with NHWs, with Koreans (41.3%) and South Asians (42.8%) having survival double that of NHWs (20.1%, P < 0.001). In multivariable regression, differences in stage of diagnosis and rates of resection partially explained the difference in survivorship between Asian subgroups. Conclusions: We find substantial differences in incidence, staging, histology, treatment, and survivorship from NCGC between Asian subgroups, data which challenge our traditional perceptions about gastric cancer in Asians. Both biological heterogeneity and cultural/environmental differences may underlie these findings. Impact: These data are relevant to the national discourse regarding the appropriate role of gastric cancer screening, and identifies high-risk racial/ethnic subgroups who many benefit from customized risk attenuation programs. Full Article
id Further Guidance in Implementing the Standardized 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Score By cebp.aacrjournals.org Published On :: 2020-05-01T00:05:36-07:00 The 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Score was developed to establish a simple, standardized scoring system for researchers to quantify adherence to the 2018 WCRF/AICR Cancer Prevention Recommendations and assess its impact on cancer risk and other health-related outcomes. The aim of this commentary is to clarify potential points of ambiguity in its application, focusing on aspects related to specific subscore components (physical activity, fast foods, alcohol, and sugar-sweetened drinks), how to address different data needs due to varied data collection instruments, and future exploratory score approaches. Overall, we encourage researchers to utilize the standardized score to enhance comparability across populations and countries. Researchers who may adapt or augment the 2018 WCRF/AICR Score are strongly encouraged to provide detailed descriptions of their methods to promote transparency and reproducibility. Full Article
id Detecting {beta}-Galactosidase-Labeled Cells By cshprotocols.cshlp.org Published On :: 2020-05-01T06:29:31-07:00 β-Galactosidase has been used extensively both as a label in enzyme immunoassays and for immunocytochemistry. One good substrate is 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside (X-gal), which gives an intense blue product. The product is stable and insoluble in alcohol as well as H2O. Full Article
id Sensitive Determination of Infectious Titer of Recombinant Adeno-Associated Viruses (rAAVs) Using TCID50 End-Point Dilution and Quantitative Polymerase Chain Reaction (qPCR) By cshprotocols.cshlp.org Published On :: 2020-05-01T06:29:31-07:00 Adeno-associated virus (AAV) recombinants are currently the vector of choice for many gene therapy applications. As experimental therapies progress to clinical trials, the need to characterize recombinant adeno-associated viruses (rAAVs) accurately and reproducibly increases. Accurate determination of rAAV infectious titer is important for determining the activity of each vector lot and for ensuring lot-to-lot consistency. The following protocol developed in our laboratory uses a 96-well TCID50 format and quantitative polymerase chain reaction (qPCR) detection for the determination of rAAV infectious titer. Full Article
id Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer Is Associated with Indigenous American Ancestry in Latin American Women By cancerres.aacrjournals.org Published On :: 2020-05-04T05:35:17-07:00 Women of Latin American origin in the United States are more likely to be diagnosed with advanced breast cancer and have a higher risk of mortality than non-Hispanic White women. Studies in U.S. Latinas and Latin American women have reported a high incidence of HER2 positive (+) tumors; however, the factors contributing to this observation are unknown. Genome-wide genotype data for 1,312 patients from the Peruvian Genetics and Genomics of Breast Cancer Study (PEGEN-BC) were used to estimate genetic ancestry. We tested the association between HER2 status and genetic ancestry using logistic and multinomial logistic regression models. Findings were replicated in 616 samples from Mexico and Colombia. Average Indigenous American (IA) ancestry differed by subtype. In multivariate models, the odds of having an HER2+ tumor increased by a factor of 1.20 with every 10% increase in IA ancestry proportion (95% CI, 1.07–1.35; P = 0.001). The association between HER2 status and IA ancestry was independently replicated in samples from Mexico and Colombia. Results suggest that the high prevalence of HER2+ tumors in Latinas could be due in part to the presence of population-specific genetic variant(s) affecting HER2 expression in breast cancer.Significance:The positive association between Indigenous American genetic ancestry and HER2+ breast cancer suggests that the high incidence of HER2+ subtypes in Latinas might be due to population and subtype-specific genetic risk variants. Full Article