Peanut butter intake, GSTM1 genotype and hepatocellular carcinoma: a case-control study in Sudan.

OBJECTIVE: Hepatocellular carcinoma (HCC) is one of the major cancers in the world. In Sudan the incidence is thought to be high and increasing. This study aims to assess the association between peanut butter intake, as a source of aflatoxins, and the GSTM1 genotype in the etiology of HCC. METHOD: A case control study was conducted among 150 patients and 205 controls from two regions in Sudan. Food habits with special reference to peanut butter consumption, as well as peanut storage systems, have been investigated, as well as confounders such as hepatitis, drinking and smoking habits, and demographic characteristics. GSTM1 genotype was assessed in DNA extracted from blood samples (110 cases, 189 controls). RESULTS: A positive association was observed for highest vs. lowest quartile of peanut butter intake, humid storage system and HCC, with ORs (95% CI) being 3.0 (1.6-5.5) and 1.6 (1.1-2.5) respectively. The positive association with peanut butter intake was essentially limited to subjects with GSTM1 null genotype with OR for highest vs. lowest quartile 16.7 (2.7-105). CONCLUSION: Peanut butter consumption has been identified as a strong risk factor of HCC in a region with endemic aflatoxin contamination in Sudan and was essentially limited to subjects with the GSTM1 null genotype.