Predicting the radiosensitivity with Raf kinase inhibitor protein in nasopharyngeal carcinoma / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the relationship between RKIP expression and the efficiency of radiotherapy in NPC patients and evaluate the possibility of using RKIP as a predictor of radiosensitivity.Methods A total of 180 patients with NPC in Sun Yat-sen University Cancer Center without evidence of distant metastasis at initial diagnosis were enrolled in this study,who had received intensity-modulated radiotherapy alone.Patients were classified into 2 groups according to criteria belowpatients with biopsy proven recurrent diseases occurring at nasopharynx and/or neck within 5 years after radiotherapy were classified as the radioresistant group.The pathological type at relapse was the same as the previous one before treatment.Patients with a minimum follow-up of 5 years after radiotherapy without evidence of recurrence at the original site of the tumor were classified as the radiosensitive group.Patients in the 2 groups were matched according to the factors related with radiosensitivity.RKIP was examined by immunohistochemical staining before radiotherapy.The relationship between RKIP expression and the effect of radiotherapy were analyzed.Results The positive rate of the RKIP expression in the radiosensitive group versus the radioresistant group was 80.0％ versus 26.7％.The positive rate (x2 =12.498,P ＜0.01) and the intensity of the RKIP expression (x2 =51.429,P ＜ 0.01) were significantly different between 2 groups with a negative correlation with radio-resistance to NPC (r =-0.344,-0.535,respectively,P ＜ 0.01).Based on the RKIP expression,the radiosensitivity,specificity,accuracy,positive predictive value,negative predictive value,false positive and false negative were predicted as follows80.0％,73.3％,77.2％,75.0％,78.6％,26.7％,and 20.0％,respectively.Conclusions RKIP protein shows negative correlation with radioresistance to NPC and could serve as a biomarker in preliminarily screening the intrinsic radiosensitivity of NPC.