Breast cancer is the most frequent malignancy of women in the world and the incidence of the disease is rising faster in population groups that have hitherto enjoyed low incidence of the disease. In this study, we utilized a polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) assay to assess the relationship between a G to A transition polymorphism in codon 158 of the catechol-O-methyltransferase (COMT) gene and breast cancer risk in a case-control study recruiting 250 Nigerian women with breast cancer and 250 age-matched controls. In the final multivariate logistic regression model in all women, carrying at least one of low-activity allele of the COMT gene (COMT [Val/Met] + COMT [Met/Met]) was associated with a significant 33% reduced risk of breast cancer (0R = 0.57, 95% CI = 0.36-0.91). In premenopausal women, harboring at least one low- activity COMT (Met) allele conferred a non-significant 31% reduced risk of breast cancer (OR = 0.69, 95% CI 0.40-1.18) while there was a 14% reduced risk of postmenopausal breast cancer (OR = 0.86, 95% CI 0.46-1.61) for carrying at least one low-activity COMT (Met) allele. Our results suggest that harboring the COMT polymorphism appears to confer some protection against breast cancer risk in this population. We suggest more studies to further evaluate the contribution of this polymorphism to breast cancer susceptibility in sub-Saharan African populations.

[Proc Amer Assoc Cancer Res, Volume 47, 2006]