XRCC6 and breast cancer: Relevant studies have demonstrated that in breast cancer, nCLU binds to cytosolic Ku70 and causes X-ray-induced cell death.[27,28] Additionally, Kim et al found that the binding of nCLU with Bcl-XL and perhaps other antiapoptotic proteins, which led to the release and activation of Bax, was responsible for nCLU overexpression causing significant apoptotic cell death.[29]