[932] The Relationship between EZH2 Expression and Renal Cell Carcinoma

Hye Won Lee, Ji Young Park, Ilseon Hwang, Hye Ra Jung, Sun Young Kwon, Yu Na Kang, Sang Pyo Kim, Kun Young Kwon, Sang Sook Lee, Mi Sun Choe. Keimyung University School of Medicine, Daegu, Korea

Background: Enhancer of zeste 2 (EZH2) is a member of the Polycomb group proteins and part of Polycomb repressive complex 2. The EZH2 is important for transcriptional repression. Particularly, aberration of EZH2 has been implicated in oncogenesis and progression of various neoplasms. Renal cell carcinoma (RCC) remains a major cause of morbidity and mortality, and the incidence of RCC in the worldwide has continued to rise. Clear cell type make up the majority of the RCC. The objective of this study was to evaluate EZH2 expression in clear cell RCC and correlate the expression with prognostic factors.
Design: Tissue was obtained from surgically resected specimens of 176 patients who were diagnosed with clear cell RCC. EZH2 expression was determined by immunohistochemical staining. EZH2 expression with variable intensities was observed predominantly in nuclei and grouped into low and high expression. The association of EZH2 expression with clinicopathological characters and prognosis was determined by statistical analyses.
Results: High expression of EZH2 was significantly correlated with higher pT stage and histologic grade or more frequent distant metastases (P = 0.001, 0.025 and 0.024, respectively). On the other hand, EZH2 had no significant association with age, gender or pN stage (P > 0.05).

Associations between clinicopathological parameters and patients' outcome

	Distant metastases (P-value)	DWD (P-value)
EZH2 Low vs. High	0.024**	0.073
Age (yr) ≤56 vs. > 56	0.02**	0.038**
Gender Male vs. Female	0.538	0.269
Histologic grade I-II vs. III-IV	0.011**	0.079
pT stage T1-2 vs. T3-4	0.0001**	0.007**
TNM stage I-II vs. III-IV	0.0001**	0.0001**

NOTE: P-values of χ2-tests are indicated; *, Fisher's exact tests are indicated; **, Statistically significant, P < 0.05; DWD, death with disease

Kaplan-Meier survival analyses with log-rank tests displayed that patients with high EZH2 expression had a significantly shorter disease-free survival (P = 0.019). EZH2 expression was associated with overall survival; however, differences did not reach statistical significance (P = 0.066).


Conclusions: From our results, we propose that EZH2 is a useful prognostic marker for aggressive behavior including distant metastases of clear cell RCC.
Category: Genitourinary (including renal tumors)

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 157, Tuesday Morning