Impact of Suppressor of Mothers Against Decapentaplegic (SMAD) 7 Gene Single Nucleotide Polymorphisms on Colorectal Cancer Risk and Prognosis

Colorectal cancer (CRC) is a prevalent diagnosis worldwide with significant associated mortality. Single nucleotide polymorphic (SNP) variants have been identified as being associated with CRC risk. Although SMAD7 SNPs have been associated with the risk of developing CRC, their prognostic effect is still unclear. We carried out a case-control study to establish an association between genotypes of the suppressor of mothers against decapentaplegic (SMAD) 7 SNP rs4464148, rs4939827, and rs12953717 and CRC risk. Furthermore, we retrospectively assessed whether these SNPs had prognostic implications in CRC patients by evaluating survival with Kaplan-Meier curves and Cox regression. Only the CT genotype of the rs4939827 variant showed an association with CRC risk, and no genotype (CC, CT, or TT) of any of the three SNPs was shown to have prognostic implications in overall survival. Our study failed to show an association between certain SNP genotypes and the risk of CRC, which has already been well documented in two meta-analyses. Furthermore, it showed no prognostic relevance for these SNPs. More studies are needed to understand whether there are population variations or haplotype effects that could disturb the evaluation of these results.