Associations differ by sex for catechol-O-methyltransferase genotypes and bladder cancer risk in South Egypt.

OBJECTIVES: To examine associations between urinary bladder cancer risk and polymorphisms of the gene encoding the catechol estrogen-metabolizing enzyme, catechol-O-methyltransferase (COMT), among Egyptian women and men. MATERIALS AND METHODS: We used questionnaire and genotype data from a case-control study in Egypt. This analysis focused on South Egypt cases with confirmed urothelial (UC) or squamous cell (SCC) carcinoma of the bladder, and controls frequency-matched on sex, 5-year age-group, and residence governorate. Real-time PCR on blood specimen DNA was used to determine COMT genotypes encoding for Val/Val, Val/Met, and Met/Met, the enzyme forms associated with high, intermediate, or low activity, respectively. RESULTS: The study sample, which included 255 women and 666 men, consisted of 394 cases with histologically confirmed UC (225) or SCC (n = 169), and 527 controls. The odds of having either type of bladder cancer were lower among men with genotypes encoding Val/Met or Met/Met than among those with the genotype encoding Val/Val, even after adjustment for other factors, such as smoking and schistosomiasis history [adjusted odds ratio (AOR): 0.64; 95% confidence interval (CI): 0.43, 0.96]; however, the association was statistically significant for SCC (AOR 0.57; 95% CI: 0.34, 0.96) but marginal for UC (AOR: 0.64; 95% CI: 0.39, 1.02). No significant associations were detected between bladder cancer risk and COMT genotypes among postmenopausal women. CONCLUSIONS: These findings suggest that even after controlling for established risk factors, the involvement of COMT genotypes in bladder cancer risk differs among men compared with women in South Egypt.