XRCC6 and colorectal carcinoma: In conclusion, our research uncovers a novel mechanism by which SIK2 contributes to the radioresistance of CRC: SIK2 binds to VCP and promotes its hyperphosphorylation, which enhances VCP's function in extracting K48‐linked ubiquitin‐conjugated proteins, such as K48‐modified Ku70/80 rings, from chromatin.