The expression of K-ras, MSH2 and MLH1 in the serrated lesions from the experimental group was not observed to be significantly different compared with that of the cancer tissues from the experimental group (P<1.000, 0.403 and 0.357, respectively), while a significant difference in the expression of MGMT was found between the groups (P=0.0022). This evidence concerns the gene MLH1 and cancer.