Abstract: Objective To investigate the expression of p53 and p21WAF1 in the NPC cells before and after intratumoral injection of recombinant adenovirus p53(rAd-p53) and their relationships with short-term prognosis. Methods The expression of p53 and p21WAF1 protein were examined by immunochemistry in 12 cases of chronic nasopharynxitis and 63 cases with advanced stage nasopharyngeal carcinoma.Sixty-three cases of NPC were randomly divided into two groups:the p53 therapy group(32 cases) for rAd-p53 intratumoral injection plus radiotherapy and chemotherapy;and the common therapy group(31 cases) for radiotherapy and chemotherapy.The expression levels of p53 and p21WAF1 in biopsy samples from all the cases before and at the 20 Gy of radiotherapy were analyzed;And their relationship with prognosis was also analyzed. Results The expression of p53 and p21WAF1 in 63 cases of NPC was 49.21% and 46.03%,respectively.There was a significant difference between NPC and chronic pharyngitis tissues (P ＜0.05).There was correlation between p53 and p21WAF1 expression in NPC tissues (r_s=0.556,P=0.000).Before radiotherapy and at the 20 Gy of radiotherapy,positive expression of p21WAF1 in the p53 therapy group was significant difference (P＜0.05);and the positive expression of p53 and p21WAF1 was related to the 1-year disease-free survival rate in both groups (P＜0.05). Conclusion The positive expressions of p53 and p21WAF1 after rAd-p53 intratumoral injection may play an important role in repressing the recurrence and metastasis of NPC,which indicates a better prognosis.