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Extranodal NK/T-cell lymphoma (ENKTL) is an Epstein-Barr virus (EBV) associated lymphoma, prevalent in Asia and Latin America. Studies in Asian cohorts have identified some recurrent gene mutations in ENKTL; however, the mutational landscape of ENKTL in Latin America is unknown. In this study, we investigated the mutational profile and EBV strains of 71 ENKTL cases from Latin America (42 from Mexico, 17 from Peru, and 12 from Argentina) and compared it with Asian cohorts. The mutational analysis was performed by next generation sequencing (NGS) using an Ion AmpliSeq™ custom panel covering for the most frequently mutated genes identified in ENKTL. STAT3 was the most frequent mutated gene (16 cases: 23%), followed by MSN (10 cases; 14%), BCOR (9 cases; 13%), DDX3X (6 cases; 8%), TP53 (6 cases; 8%), MGA (3 cases; 4%), JAK3 (2 cases; 3%), and STAT5B (1 case; 1%). Mutations in STAT3, BCOR, and DDX3X were nearly mutually exclusive, suggesting different molecular pathways involved in the pathogenesis of ENKTL; whereas mutations in MGA, MSN, and TP53 were concomitant with other mutations. Most cases (75%) carried Type A EBV without the 30-bp LMP1 gene deletion. The overall survival was significantly associated with serum LDH level, Eastern Cooperative Oncology Group (ECOG) performance status, International Prognostic Index (IPI) score, and therapy (p < 0.05), but not associated with any mutation, EBV strain or deletion in EBV LMP1 gene. In conclusion, mutational analysis of ENKTL from Latin America reveals frequent gene mutations leading to activation of the JAK-STAT pathway (25%), mostly STAT3. Compared to Asian cohorts, BCOR, DDX3X  and TP53 mutations were also identified but with different frequencies. None of these mutations were associated with prognosis.

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., (©2020 American Association for Cancer Research.)