Polymorphism of DNA mismatch repair genes in endometrial cancer

Endometrial cancer (EC) is the second most common malignancy associated with hereditary non-polyposis colorectal cancer (HNPCC) family. The development of HNPCC is associated with defects in DNA mismatch repair (MMR) pathway resulting in microsatellite instability (MSI). MSI is present in a greater number of EC than can be accounted for by inherited MMR mutations, therefore alternative mechanisms may underline defective MMR in EC, including polymorphic variation.

We checked the association between EC occurrence and two polymorphisms of MMR genes: a 1032G>A (rs4987188) transition in the hMSH2 gene resulting in a Gly22Asp substitution and a -93G>A (rs1800734) transition in the promoter of the hMLH1 gene.

These polymorphisms were genotyped in DNA from peripheral blood lymphocytes of 100 EC patients and 100 age-matched women by restriction fragment length polymorphism PCR.

A positive association (OR 4.18; 95% CI 2.23-7.84) was found for the G/A genotype of the -93G>A polymorphism of the hMLH1 gene and EC occurrence. On the ot-her hand, the A allele of this polymorphism was associated with decreased EC occurrence. The Gly/Gly genotype slightly increased the effect of the -93G>A-G/A genotype (OR 4.52; CI 2.41-8.49). Our results suggest that the -93G>A polymorphism of the hMLH1 gene singly and in combination with the Gly322Asp polymorphism of the hMSH2 gene may increase the risk of EC.