The multiethnic cohort study: exploring genes, lifestyle and cancer risk

Asian migrants to the United States have shown major changes in rates of several important cancers. An understanding of the reasons for these changing rates provides an important insight into cancer causation.The Multiethnic Cohort (MEC) Study was established to use variations in specific rates of disease in different ethnic groups to characterize the environmental and genetic contributions to certain common cancers.In the MEC, breast cancer rates are highest among native Hawaiians and Japanese. Differences in established breast cancer risk factors do not explain these high risks.Prostate cancer rates are highest in African Americans. Because only age and family history are additional known risk factors for prostate cancer, systematic research is underway to identify cancer-associated variants in the androgen growth factor and in as yet unidentified gene families.Variation in coding and regulatory regions of various genes contributes to susceptibility to many chronic diseases, such as cancer. Clarifying this variation using population-based protocols necessitates the careful characterization of each gene. For association studies, large and well-characterized populations of diseased and matched non-diseased individuals are crucial to minimize the limitations that have applied to many studies published so far.Variation in disease-associated alleles by race and ethnic group is a key strength of the MEC and other such large population-based studies.