Role of KIT expression in the prognosis of clear cell renal cell carcinomas in Chinese patients

To investigate the expression of KIT in clear cell renal cell carcinomas, and to reveal the relationships between KIT status and clinicopathological features and survival of clear cell renal cell carcinomas. The expression of KIT was tested immunohistochemically in 119 specimens of clear cell renal cell carcinoma. Their correlations to clinicopathological parameters were compared and discussed. Kaplan-Meier method was used to determine the survival between KIT-positive and KIT-negative patients. Multivariate analysis was performed using the Cox-regression model for overall survival. A total of 13 out of 119 cases of clear cell renal cell carcinomas (10.9%) were demonstrated consistent overexpression of KIT. There was statistical significance in the correlation between KIT expression and tumor size (P < 0.01), pathological stage (P < 0.01), tumor grade (P < 0.01) and P53 (0.01 < P < 0.05). On multivariate analysis, positive KIT expression presented an independent predictive factor for decreased overall survival (hazard ratio 17.26, P = 0.005). The estimated mean survival time was 25.6 months for KIT-positive patients and 56.9 months for KIT negative patients, P < 0.001. The expression of KIT was significantly associated with tumor size, pathological stage, tumor grade and P53 in clear cell renal cell carcinomas. The expression of KIT is an important survival predicting factor for patients with clear cell renal cell carcinoma.