XRCC6P5 and nasopharyngeal carcinoma: Phosphorylated H2AX is a mediator in response to DNA damage, which recruits DNA repair proteins at the chromatin lesion to carry out repair, and it has been reported to be associated with numerous cancers, including oral squamous cell, esophageal, breast, non-small cell lung, gastric, bladder, colorectal carcinoma, as well as NPC [71-79], suggesting that DNA damage occurs and may play a role in the development of cancers although this correlation remains to be understood.