MLH1 and ovarian cancer: Zhao et al. found that the increased expression of DNMT3B in ovarian cancer cells increased the methylation level of the promoter regions of anti-oncogenes such as hMLH1 (mismatch repair gene human mutL homolog-1), p16 and p53. These methylation changes decreased the expression of the hMLH1, p16 and p53 genes and promoted tumor development [42,107].