Radioresistance induced residual or recurrent tumor acts as a main cause of nasopharyngeal carcinoma(NPC)treatment failure.Thus It is necessary to investigate mechanism of NPC radioresistance and identify predictive markers of NPC prognosis and radioresistance.In this study,we identified RPA3 as a candidate radioresistant marker via RNA-seq of NPC sample.In vitro studies further confirmed that RPA3 affected radiosensitivity of NPC cells.