XRCC2 and breast cancer: Haplotype association tests showed that the CTC haplotype defined by the SNPs rs3218552|rs3218550|rs3218536 on the XRCC2 gene on chromosome 7 (P = 0.008762) and the CA haplotype defined by the SNPs rs1049620|rs6917 on the PHB gene on chromosome 17 (P = 0.006718) were significantly associated with increased risk of breast cancer (Table 3).