Radiotherapy is widely used for the definitive and adjuvant treatment of numerous cancers[1].However,resistance to radiotherapy remains an important concern[2].Various factors including p53 mutation or deletion[3],overexpression of DNA repair proteins[4],and tumor microenvironment[5]have been proposed to play roles in radioresistance.Among the radioresistant factors,p53 mutation or deletion is regarded as a good candidate for radioresistant markers[6].The tumor suppressor p53 is well established as the guardian of the genome,regulating cell cycle arrest,DNA repair,senescence,and apoptosis[7].Mutation of p53 occurs in more than 50%of human cancers,which significantly increases cellular resistance to-irradiation[8].Additionally,there is growing evidence that mutation or deletion of p53 tumors cells is inherently resistant to radiation and perhaps other conventional anticancer treatments,i.e.,chemotherapy[9].This intrinsic mechanism of resistance is responsible for a significant number of tumor recurrences[10].
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