Microsomal epoxide hydrolase genotypes and the risk for head and neck cancer

Abstract

Microsomal epoxide hydrolase (mEH) is an enzyme involved in the metabolism of (pre)carcinogens in tobacco smoke. We investigated whether functional genetic polymorphisms in mEH may have a risk-modifying effect on head and neck carcinogenesis. Blood from 429 patients with oral, pharyngeal, and laryngeal carcinoma and 419 healthy subjects was investigated for mEH polymorphisms. Logistic regression analysis did not show differences in mEH genotype distributions between patients and controls, when categorized according to predicted mEH enzyme activity. Also no differences were found when evaluated according to tumor localization, sex, or tobacco consumption. A significantly higher incidence of the 139Arg/Arg variant was found in patients with hypopharyngeal carcinoma compared with controls (OR = 4.39, 95% CI = 1.45 to 13.35). In contrast to earlier reports, we could not demonstrate a risk-modifying effect of genetic polymorphisms in mEH on head and neck carcinogenesis, except for the predicted high activity variant in patients with hypopharyngeal carcinoma.