A significant decrease in protein expression was found in patients with aberrant methylation of hMLH1 (P < 0.01) and E-cadherin (P < 0.05), and aberrant methylation of hMLH1 was also found in 14.3% of patients with atypical endometrial hyperplasia (AEH). Here, MLH1 is linked to atypical endometrial hyperplasia.