XRCC6 and cancer: Moreover, apoptosis was induced by activating caspase-3 and caspase-7, with the split-off PARP-1, high γH2AX expression, and a decrease of repair proteins Ku70 and Ku80 BRCA-1, BRCA-2, and Rad-51 of NHEJ and HR, respectively, increasing to radiosensitivity in this cancer (50).