Review of studies on metabolic genes and cancer in populations of African descent
Genetic polymorphisms described for a number of enzymes involved in the metabolism of tobacco carcinogens and alcohol have been linked to increase cancer risk. Racial disparities in cancer between whites and populations of African descent are well documented. In addition to differences in access to health care, both environment and genetic factors and their interaction may contribute to the increased cancer risk in minority populations. We reviewed the literature to identify case-control studies that included subjects of African descent. Meta-analyses investigating the association of genetic polymorphisms in tobacco metabolic genes and cancer were performed. Although several genes and cancers have been studied, only one or two studies per gene for each cancer site have been published, with the exception of breast (CYP1A1 and CYP1B1), lung (GSTM1, CYP1A1, and NQO1), and prostate (CYP3A4 A293G and CYP17). Marginal statistically significant associations were observed for CYP3A4 A293G and CYP17 5'UTR polymorphisms and prostate cancer. Our findings support the need for additional genetic association studies of breast, prostate, and lung cancers that include a larger number of minority participants. Because incidence and mortality rates for these cancers rank highest among populations of African descent, concentrated research in these areas are warranted.