Abstract: Objective Using COX multivariate analysis and ROC curve to evaluate the prognostic value of DNA repair gene in patients with Nasopharyngeal carcinoma. Methods Between May 2007 and February 2012, all 100 untreated patients with NPC, who were planned to receive IMRT at the People's Hospital of Guangxi Autonomous Region were enrolled in this study. Screening for more than 1 year follow-up of 71 cases, formalin-fixed tumor biopsy specimens from 71 untreated patients with NPC were analyzed by immunohistochemical methods. Spearman's analysis was put into use in the correlation of DNA-PKcs and BRCA1 expression levels and clinical characteristics. Kaplan-Meier survival curves analyzed the relationship between expression of DNA-PKcs and BRCA1 and prognostic groups which were established by ROC curves. And Cox proportional hazards regression multi-factor survival analysis was carried out on the prognosis at last. Results 1) There was a significant positive correlation between the expression level of DNA-PKcs and survival time of patients(P＜0.05). 2) Moreover, patients with high DNA-PKcs expression had significantly better survival than patients with low levels of DNA-PKcs(P＜0.01). 3) On multivariate analysis, only DNA-PKcs expression level is an independent prognostic factor(P＜0.01). No significant association was found between the level of BRCA1 expression and the clinical outcome. Conclusions DNA-PKcs expression level was an independent factor in prognostic and the patients with high level had a better survival.

Key words: Nasopharyngeal carcinoma, COXmultivariate analysis, ROC curve, DNA repair genes, prognosis