XRCC1 and cancer: Additionally, our study found significant combined effects of TP53 Arg249Ser variants with XRCC1 Arg194Trp and Arg399Gln, XRCC2 Arg188His, and XRCC3 Thr241Met, indicating increased GI cancer risk, underscoring the importance of the SNP-SNP interactions in determining cancer susceptibility within the studied population.