Association of CYP3A5*3 and CYP3A5*6 Polymorphisms with Breast Cancer Risk

CYP3A5 gene is located on chromosome 7q21.1 and is responsible for the metabolism of over 50% of all clinically used drugs. 250 breast cancer and same number of healthy age matched controls were analyzed for the polymorphisms of CYP3A5*3 and CYP3A5*6 by polymerase chain reaction-restriction fragment length polymorphism. The normal wild type allele CYP3A5*1 produces correct transcript and individuals with at least one CYP3A5*1 allele can express CYP3A5 at higher levels. In the present study, the frequency of heterozygotes for CYP3A5*1 (1/3) was significantly increased in breast cancer (53.0%) when compared to controls (41.4%) with corresponding increase in CYP3A5*1 allele frequency. The frequency of 3/3 genotype was increased in postmenopausal (40.0%) patients with high BMI, ER, PR and HER2/neu positive status and in housewife group. There was an increase of 1/3 genotype frequency in patients with positive family history and agricultural laborers (55.6%). In conclusion our results suggested that the CYP3A5*3 polymorphism might influence the breast cancer etiology which mainly depends on the type of exposure. CYP3A5*6 allele was not observed in cases as well as in controls.