ABSTRACT
Most cancers result from an interaction between genetic and environmental factors and these factors can determine an individual’s cancer risk. Cancer is a complex disease and can be caused by a combination of multiple gene variants, each with a weak to moderate effect, interacting with each other and with the environment. Identification of the gene and gene variants involved in familial clustering of cancer is challenging. Several approaches to identify common alleles in cancer-associated genes are emerging. Direct gene analysis of large cohorts of patients and controls is feasible with new technologies. Low to moderate risk may be assessed for relatives to cancer patients. Moderate risk assessment can also be performed for patients without family history of cancer but with bilateral disease or multiple cancers. However, the influence the common gene variants may have on an individual’s cancer risk cannot currently be determined.
