MGMT and breast cancer: In contrast, it might produce chemoresistance to anticancer treatment, therefore leading to treatment failure.[12] The loss of MGMT expression was mainly due to epigenetic event other than the deletions or rearrangements of the gene.[13] The hypermethylation of the CpG islands on MGMT gene promoter significantly silenced the MGMT gene.[14] In recent studies, significant associations between MGMT promoter hypermethylation and glioblastoma, breast cancer, and colorectal cancer were found.