In this study the influence of MSH3 and IL-6 signaling pathway polymorphisms (MSH3 exon 1, MSH3+3133A/G, IL-6-174G/C, IL-6R+48892A/C, and gp130+148G/C) on the occurrence of different types of microsatellite instability in sporadic CRC was examined by PCR–RFLP and real-time PCR SNP analyses. The gene discussed is IL6; the disease is colorectal carcinoma.