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; 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). CONCLUSIONS: 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.