Histone deacetylation, lysine-specific histone-H3 methylation, and promoter region CpG methylation modulates transcription of tumor-suppressor genes (CDKN2A, TP53, APC, BRCA1); DNA mismatch-repair genes (MLH1 or the O6-methyl-guanine-DNA methyltransferase gene, MGMT). This evidence concerns the gene TP53 and neoplasm.