CDKN2A and neoplasm: During the initiation stages, epigenetic modifications mimic the effect of genetic damage by altering the expression of tumor suppressor genes, thus compromising the tumor suppressor function of the senescence program; for example, silencing of tumor suppressor genes by promoter DNA hypermethylation and chromatin hypoacetylation, which may affect the expression of diverse genes including p53, RB1, p16INK4A, Von Hippel-Landau tumor suppressor (VHL) and MutL protein homologue 1 (MLH1) [109,162,163,168-170].