[The detection of protein expression of clusterin and Ki-67 and the status of cell apoptosis in bladder transitional cell carcinoma]

Abstract

Objective: To investigate the expression of clusterin protein in bladder transitional cell carcinoma (BTCC) and it's association with tumor cell proliferation and apoptosis.

Methods: A tissue microarray (TMA) containing 87 informative cases of BTCCs was constructed firstly. The methods of immunohistochemistry and terminal deoxynucleotidyl transferase-mediated nick end-labeling were then used to examine the expression of clusterin and Ki-67 protein and the status of cell apoptosis in BTCC, respectively, and the correlations between different markers and the clusterin expression associated with patients' clinico-pathological features were evaluated.

Results: In TMA of 87 BTCCs, 37 (43%) cases were observed overexpression of clusterin. A significant association of clusterin expression with BTCC's pathological grade, as well as with tumors clinical stage was observed (P < 0.01), where the frequency of overexpression of clusterin in poor differentiated BTCCs (G(3), 71%) and tumors in more advanced stage (T(2-4), 62%) was significantly higher than that in well differentiated BTCCs (G(1-2), 29%) and tumors in early stage (T(a-1), 28%). In addition, a significant correlation between clusterin expression and tumors apoptotic index (AI) was evaluated (P < 0.01), in which 57% of BTCCs with overexpression of clusterin were observed a lower AI, while 72% of tumors with normal expression of this protein showed a higher AI, but no correlation between clusterin and Ki-67 expression.

Conclusions: The overexpression of clusterin is associated positively with BTCC's malignant clinical phenotypes including tumor's differentiation and invasive depth, and it is correlated inversely with AI of tumor cells.