Clinical studies have identified specific genetic variants in dihydropyrimidine dehydrogenase (DPD; DPYD gene) as predictors of severe adverse toxicity to the commonly used chemotherapeutic 5‐fluorouracil (5‐FU); however, these studies have focused on European and European‐American populations. Our laboratory recently demonstrated that additional variants in non‐European haplotypes are predictive of 5‐FU toxicity. The objective of this study was to identify potential risk variants in an understudied East African population relevant to our institution's catchment area. The DPYD protein‐coding region was sequenced in 588 individuals of Somali or Kenyan ancestry living in central/southeast Minnesota. Twelve novel nonsynonymous variants were identified, seven of which significantly decreased DPD activity in vitro. The commonly reported toxicity‐associated variants, *2A, D949V, and I560S, were not detected in any individuals. Overall, this study demonstrates a critical limitation in our knowledge of pharmacogenetic predictors of 5‐FU toxicity, which has been based on clinical studies conducted in populations of limited diversity.
Increased Prevalence of Metabolic Risk Factors in Asian Americans With Hepatocellular Carcinoma
Background: We used metabolic risk factors to estimate the prevalence and clinical significance of nonalcoholic fatty liver disease in Asian Americans with hepatocellular carcinoma (HCC). Methods: This is a retrospective cohort study of 824 consecutive Asian HCC patients at Stanford University Medical Center from 1998 to 2015. Patients were subdivided as: Chinese, other East Asian (Japanese and Korean), South East Asian (Vietnamese, Thai, and Laotian), Maritime South East Asian (MSEA: Malaysian, Indonesian, Filipino, and Singaporean), and South West Asian (Indian, Pakistani, and Middle Eastern). Metabolic risk factors studied were body mass index, hypertension, type II diabetes, and hyperlipidemia. Results: Most patients were male (76%) with mean age 63 years. Metabolic risk factors were highly prevalent on presentation and increased over time (P<0.001), as did the prevalence of cryptogenic HCC (P<0.004). Compared with other Asian subgroups, MSEAs had the highest body mass index (26.3) and higher rates of type II diabetes (44% vs. 23% to 35%, P=0.004), hypertension (59% vs. 38% to 55%, P=0.04), and cryptogenic HCC (15% vs. 4% to 10%, P=0.01). They were more likely to be symptomatic on presentation (44% vs. 32% to 58%, P=0.07), less likely to present within Milan criteria (34% vs. 35% to 63%, P<0.0001), and trended toward decreased 10-year survival rates compared with other ethnic subgroups (9% vs. 25% to 32%, P=0.07). Conclusions: Metabolic risk factors were increasingly prevalent among Asian Americans with HCC. MSEAs, who had the highest incidence of these risk factors, had more advanced tumor stage and trended toward worse survival.