PRKDC and nasopharyngeal carcinoma: The central research on EBV-regulated radiation response has focused on LMP-1, which is expressed in most EBV-associated malignancies.LMP-1 inhibits DNA double-strand break repair by inhibiting the phosphorylation and activity of DNA-PKcs, a key enzyme of the NHEJ pathway in nasopharyngeal carcinoma (NPC), and by inhibiting ATM repair of DNA double-strand breaks [40].