MGMT and colorectal cancer: More than half of the colorectal cancer present hypermethylation in at least one promoter region of tumor suppressor genes (DAPK—gene associated to apoptosis linked to protein kinase; p16INK4a and p14ARF—genes involved in the cell cycle), repair genes (MGMT-O6-methylguanine-DNA methyltransferase; hMLH1-human homolog of bacterial MutL) and genes involved in progression and metastases (TIMP3, CXCL12, ID4, and IRF8) [56].