Polymorphisms have been identified in proto-oncogenes and tumor suppressor genes that
predispose people to cancer. Recent evidence indicates that genomic imprinting, an
epigenetic form of gene regulation that results in uniparental gene expression, can also
function as a cancer predisposing event. Thus, cancer susceptibility is increased by both
Mendelian inherited genetic and non-Mendelian inherited epigenetic events. Consequently,
chemical and physical agents cannot only induce cancer through the formation of genetic …