To address the question whether the expression levels of the five proteins may affect the radiosensitivity of CNE2-RR, we selected NFBD1, one of the five proteins, to be further studied because our previous study showed that the downregulation of NFBD1 significantly enhanced the radiosensitivity and chemosensitivity through impairing IR-inducing the activity of HRR pathway in NPC cells 17, 18. The gene discussed is MDC1; the disease is nasopharyngeal carcinoma.