Expression of EZH2 in renal cell carcinoma as a novel prognostic marker

Enhancer of zeste homolog 2 (EZH2) is a member of the Polycomb group proteins and a part of Polycomb repressive complex 2. EZH2 is important for transcriptional regulation through nucleosome modification and interaction with other transcription factors. Particularly, aberration of EZH2 has been implicated in oncogenesis and progression of various neoplasms. The objective of this study was to evaluate EZH2 expression in renal cell carcinoma (RCC), especially clear cell RCC (CRCC) and correlate the expression with prognostic factors. EZH2 expression was determined by immunohistochemical staining with additional Western blotting. High expression of EZH2 was significantly correlated with higher pT stage or more frequent distant metastases (P= 0.001 and 0.024, respectively). Survival analyses displayed that patients with high EZH2 expression had a significantly shorter disease-free survival than those with low expression (P= 0.019). High expression of EZH2 tended to reduce the overall survival, however, differences did not reach statistical significance (P= 0.066). From our results, we propose that EZH2 is a useful prognostic marker for aggressive behavior of CRCC and may be applicable as a therapeutic target molecule.