Abstract: Objectives To examine the level of N-WASP expression in clear cell renal cell carcinoma (CCRCC) and its association with clinicopathological features. Methods Immunohistochemical staining for N-WASP was performed on tissue microarrays constructed from tumor and para-tumor tissue obtained from 73 CCRCC patients. The difference in N-WASP expression between tumor tissue and adjacent normal renal tissue was examined. Correlations between N-WASP expression in the tumor and clinicopathological parameters were analyzed and the relationship between N-WASP expression and overall survival also assessed. Univariate and multivariate survival analyses were performed using the Cox proportional hazards regression model. Results N-WASP expression was reduced in tumor tissues (P<0.001). Patients with weak-to-moderate N-WASP expression tended to have a longer over-all survival than those with a high tumor N-WASP level (P<0.01). A higher level of N-WASP expression in the tumor was an indicator of poor survival in CCRCC patients (P<0.01). N-WASP was an independent predictor for overall survival (P<0.05). Conclusions N-WASP was significantly downregulated in CCRCC and could serve as a promising prognostic biomarker for predicting clinical outcome.

Key words: Biomarker, Clear cell renal cell carcinoma, Neural Wiskott–Aldrich syndrome protein, Tissue microarray