Two main pathway are responsible for DNA DSB repair, which are NHEJ and HR 42.In this study, we found that CQ combined with zinc remarkably down-regulated the key proteins including BRCA1, BRCA2, RAD-51 (HR pathway) as well as Ku70 and 80 (NHEJ pathway) in NPC stem-like cells, suggesting radiosensitization induced by CQ combined with zinc might be mediated by suppression of DNA damage repair 43. Here, XRCC6 is linked to nasopharyngeal carcinoma.