Estrogens, Genetic Polymorphisms and Breast Cancer Risk

Abstract : This study is aimed at evaluating the role of polymorphisms in the genes encoding enzymes responsible for the biosynthesis and degradation of estrogens and its metabolites in susceptibility to breast cancer in Nigerian women. A case-control study is being undertaken to investigate the exposure level to estrogen and its metabolites in these women by examining the genotype frequencies of the genes encoding aromatase, estrogen hydroxylase and catechol-O-methyltransferase, the three major enzyme systems involved in the biosynthesis and degradation of estrogen and its metabolites. Polymorphisms in these genes have been reported to influence breast cancer risk in African American women. Since Nigerian women share common genetic ancestry with African American women, it is biologically plausible to speculate that similar genetic factors may be acting to determine breast cancer risk in both populations. The first 20 months of the study (i.e., August 2002 and April 2004) was spent in recruiting 500 study participants from Nigeria and transferring study documents and biological samples from Nigeria to the University of Pittsburgh. Data entry was accomplished in May and June 2004 and descriptive data analysis is currently on going. DNA extraction is underway. Genotyping will be completed in the final year.