Polymorphism of MSH2 Gly322Asp and MLH1 -93G>A in non-familial colon cancer - a case-controlled study

Our aim was to determine the effect of the single nucleotide polymorphisms (SNP) -93G>A of the MLH1 gene (rs1800734) and Gly322Asp of the MSH2 gene (rs4987188) on the risk of colon cancer (CC) and identify any relationship with clinical factors.

The study included 144 unrelated patients with sporadic CC (71 males; mean age: 61.7 ±11 years) and 151 control patients (74 males; mean age: 63 ±11 years). DNA was extracted from peripheral blood lymphocytes, and genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism.

In our population, the homozygous G/G genotype of the -93G>AMLH1 gene increased the risk of sporadic CC (OR = 2.07; 95% CI: 1.11-3.83; p < 0.02). For A/G and A/A genotypes, the MLH1-93G>A polymorphism was significantly more common in women (p = 0.034). The SNP demonstrated differences in allele distribution according to the location of the tumor, i.e. right vs. left side (p = 0.014), and disease recurrence (p = 0.022). Significant differences were found in the occurrence of Gly322Asp of MSH2 with regard to primary and recurrent disease (p = 0.001).

The -93G>AMLH1 polymorphism plays an important role in evaluating the risk of sporadic CC. It can also be used as an indicator in some patients with left-sided and recurrent tumors. MSH2 Gly322Asp is a potential marker in patients with risk of recurrence.