Relationship between hMLH1 Expression-Deficiency and It's Promoter Methylation in Endometriosis

Objective To study the methylation of human mutL homolog 1(hMLH1)promoter and its expression in endometriosis(EMs)and normal endometrium.Methods The protein expression of hMLH1 was analysed in 23 tissues of endometriosis(EMs group)and 20 tissues of normal endometrium(control group)by the immunohistochemistry SP method from January to October 2009.DNA was extracted from all these tissues.Methylation of hMLH1 was verified by methylation specificity PCR(MSP).Results The positive expression of hMLH1 in EMs group was 65%(15/23),control group was 95%(19/20).There was significant difference between two groups(P0.05).hMLH1 promoter complete and partial methylation in endometriosis was 39%(9/23),control group was 5%(1/20).There was also significant difference between two groups(P0.05).Conclusion The negative or low expression of hMLH1 was one of the most important mechanisms of endometriosis.Methylation of hMLH1 promoter was partial mechanisms.