XRCC3 and breast cancer: Further investigation of the combinatorial impact of HRR variants on BC risk showed that the XRCC2 - Arg/Arg, XRCC3 -Thr/Thr, and RAD51 - C/C genotype combination was elevated in BC cases compared to controls, thereby conferring elevated risk of BC [OR: 3.29 (95%CI: 1.17–9.23); p = 0.024] (Table 5).