Genetic Polymorphisms of CYP2E1, GSTP1, NQO1 and MPO and the Risk of Nasopharyngeal Carcinoma in a Han Chinese Population of Southern China

Five single nucleotide polymorphisms (SNPs) of CYP2E1-rs2031920, CYP2E1-rs6413432, GSTP1-rs947894, MPO-rs2333227 and NQO1-rs1800566 were genotyped by PCR-based RFLP, sequencing and TaqMan assay in 358 NPC cases and 629 controls (phase I cohort). Logistic regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals (CI). To confirm our results, sixteen tag SNPs for GSTP1, MPO, NQO1 (which 100% covered these genes), and 4 functional SNPs of CYP2E1 were genotyped in another cohort of 213 NPC cases and 230 controls (phase II cohort).No significant associations in NPC risk were observed for the five polymorphisms tested in the phase I cohort. In an additional stratified analysis for phase I, there was no significant association between cases and controls in NPC high risk population (EBV/IgA/VCA positive population). Analysis of 14 tagging SNPs within the same genes in an independent phase II cohort were in agreement with no SNPs significantly associated with NPC.Our results suggest that polymorphism of CYP2E1, GSTP1, MPO and NQO1 genes does not contribute to overall NPC risk in a Han Chinese in southern China.Nasopharyngeal carcinoma (NPC) is rare in most regions of the world; however it is a common cancer in southern China, especially in Guangdong and Guangxi Provinces. The incidence rate of NPC for males is more than 20 per 100,000 and up to 25-40 per 100,000 in some areas bordering the Xijiang River and Pearl River drainages in these two provinces[1,2]. Both environmental and genetic factors have been associated with the risk of developing NPC. Epidemiologic studies have indicated a strong influence for Epstein-Barr virus (EBV) infection, consumption of salt-preserved fish, exposure to domestic wood cooking fires, and exposure to occupational solvents in the risk for NPC[3,4]. Accumulating data have shown that genetic polymorphisms of the genes responsible for the xenobiotic enzymes which metabolize carcinogenic compounds underlie individual