Cell proliferative activity and expression of cell-cell adhesion factors (E-cadherin, alpha-, beta-, and gamma-catenin, and p120) in sarcomatoid renal cell carcinoma

Background and Objectives: Sarcomatoid RCC (renal cell carcinoma) is an unc ommon, but not rare, neoplasm which has been shown to have a much worse pro gnosis than common RCC. The current study was designed to investigate the a ssociation of proliferative activity and cell-cell adhesion molecules with sarcomatoid RCC. Methods: Proliferative activity (Ki-67 labeling index) and expression of ce ll-cell adhesion associated molecules (E-cadherin, alpha-, beta-, and gamma -catenin, and p120) were examined using immunohistochemical techniques in 11 cases of sarcomatoid RCC. Results: In six patients with sarcomatous component more than 50%, five wer e died within 24 month after diagnosis. The expression of these molecules w ithin the carcinomatous and sarcomatous components of sarcomatoid RCC was c ompared. The mean Ki-67 labeling index in the sarcomatous components (12.6% ) is statistically higher than in the carcinomatous components (3.7%) (P<0. 05). The expressions of E-cadherin, and <alpha>-, beta-, and gamma -catenin were statistically decreased in the sarcomatous components compared to the carcinomatous components. However, no differences were observed regarding p120 immunostaining. Conclusions: The findings of the current study suggest that the range of th e sarcomatous component may be a prognostic factor in RCC, and the malignan t behavior of sarcomatoid RCC is due to high cell proliferative activity an d decreased expressions of E-cadherin and alpha-,beta-, and gamma -catenin in the sarcomatous component. J. Surg. Oncol. 2001;77:123-131. (C) 2001 Wil ey-Liss, Inc.