The MLH1 -93 promoter variant influences gene expression.

The -93 SNP of MLH1 gene is associated with MLH1 gene methylation in endometrial and colorectal cancers. We undertook luciferase reporter assay and electrophoretic mobility shift assay (EMSA) to test whether the -93 SNP affects the MLH1 gene expression. The luciferase activity for -93A plasmid is significantly lower than -93G plasmid. In EMSA experiments, the -93A and -93G probes have different binding affinity to nuclear proteins of JEG3 cells. Our data indicate that -93 SNP affects MLH1 gene expression by altering protein binding to the promoter of MLH1 gene.