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 uncommon, but not rare, neoplasm which has been shown to have a much worse prognosis than common RCC. The current study was designed to investigate the association of proliferative activity and cell-cell adhesion molecules with sarcomatoid RCC.

METHODS

Proliferative activity (Ki-67 labeling index) and expression of cell-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 were died within 24 month after diagnosis. The expression of these molecules within the carcinomatous and sarcomatous components of sarcomatoid RCC was compared. 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 the sarcomatous component may be a prognostic factor in RCC, and the malignant behavior of sarcomatoid RCC is due to high cell proliferative activity and decreased expressions of E-cadherin and alpha-, beta-, and gamma-catenin in the sarcomatous component.