XRCC1 and breast cancer: Nowadays, data generated by GWAS have expanded our understanding of genetic variants that also can act as prognostic markers for multiple cancers [4], such as the SNP rs10484761 in gastric cancer [5], SNP of XRCC1 Arg399Gln both in non-small cell lung cancer [6] and breast cancer [7], the GNAS1 T393C polymorphism in gastric cancer [8], laryngeal carcinoma [9] and breast cancer [10].