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

Introduction: 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.

Material And Methods: 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.

Results: 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; < 0.02). For A/G and A/A genotypes, the MLH1-93G>A polymorphism was significantly more common in women ( = 0.034). The SNP demonstrated differences in allele distribution according to the location of the tumor, i.e. right vs. left side ( = 0.014), and disease recurrence ( = 0.022). Significant differences were found in the occurrence of Gly322Asp of with regard to primary and recurrent disease ( = 0.001).

Conclusions: The -93G>A 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.