MGMT is frequently methylated in various tumors, including gliomas (40%) [28], diffuse large B-cell lymphoma (36%) [29], colorectal cancer (46%) [30], gastric cancer (36.8%) [31], non-small cell lung cancer (21%) [32], esophageal cancer (44%) [19] and head and neck cancers (60.8%) [33]. This evidence concerns the gene MGMT and colorectal cancer.