CDKN2A and malignant colon neoplasm: HCT116 colon cancer cells were found to have genetic mutations in one allele of both CDKN2a and MLH1 and epigenetic silencing of the second allele, demonstrating the collaboration of genetic mutation and hypermethylation in achieving the second ‘hit’ to cause loss of heterozygosity and inactivation a tumor suppressor gene [20].