Association between gene expression of metabolizing enzymes and esophageal squamous cell carcinomas in China

Epidemiological studies have indicated that the incidence of esophageal squamous cell carcinoma (ESCC) is associated with environmental exposure to mutagens and carcinogens. To determine whether the basal expression level of genes involved in metabolism of carcinogens is associated with the risk of ESCC, a case-control study of 100 patients with newly diagnosed, untreated ESCC and 117 healthy controls was performed, and the relative expression levels of four metabolism genes (CYP2E1, GSTP1, MTHFR, and NQO1) were determined with quantitative real-time reverse transcription-polymerase chain reaction in peripheral blood mononuclear cells (PBMCs). Analyzed with the mean of relative expression level in the controls as the cut-off point, the result exhibited that the increased risk for ESCC was significantly associated with reduced expression of GSTP1 (odds ratio [OR]=3.644, 95% confidence interval [CI: 1.947-6.823) and NQO1 (OR=1.870, 95% CI: 1.046-3.345). When adjusted for age, sex, smoking status, and alcohol use, the increased risk for ESCC was significantly associated with reduced expression of GSTP1, MTHFR, and NQO1, and GSTP1 mRNA showed a steady association with the risk for ESCC (OR=2.640) in the model of stepwise regression analysis. Reduced expression of GSTP1 in PBMCs was significantly associated with the risk for ESCC, suggesting an important etiology clue to the early progression of ESCC in the Huaian population of China.