Evaluation of CD31 (PECAM-1) expression using tissue microarray in patients with renal cell carcinoma

Intratumoural microvessel density (MVD) has prognostic significance in selected neoplasms. To evaluate the prognostic information of MVD in renal cell carcinoma (RCC) we assessed the immunohistochemical expression of CD31 in 208 tumours using the tissue microarray technique. The expression was related to tumour cell type, TNM stage, nuclear grade and survival. CD31 expression was significantly (p < 0.001) higher in 167 conventional RCCs (clear cell) compared to 28 papillary RCCs. In conventional RCC, CD31 expression was inversely correlated to TNM stage (p = 0.024) and nuclear grade (p = 0.010). To evaluate the impact of CD31 expression on tumour-specific survival, the conventional RCC tumours were subdivided into quartiles according to the CD31 expression. In univariate analysis, patients with tumours in the quartile with the highest expression had a more favourable prognosis (p = 0.01) compared to those with lower CD31 expression. A multivariate analysis of prognostic factors in conventional RCC showed that TNM stage and nuclear grade were independent predictors of prognosis, but CD31 expression did not add further prognostic information.