XRCC6 and breast cancer: Additionally, we found that the expression of p‐RPA32 and formation of RAD51 foci, two markers of HRR, was reduced in BCKDK‐silenced breast cancer cells (Figure 1i; Figure S1f,g, Supporting Information), while the expression of the Ku70 and formation of 53BP1 foci, two markers of NHEJ, remained unaffected (Figure 1i; Figure S1f,g, Supporting Information).