Value of clusterin immunoreactivity as a predictive factor in muscle-invasive urothelial bladder carcinoma

To determine whether clusterin immunoreactivity of muscle-invasive bladder carcinoma can predict disease-related survival of patients treated by radical cystectomy.

Multi-tissue arrays were constructed from 132 tumors and stained immunohistochemically using a mouse monoclonal antibody (clone 7D1). Positive clusterin staining was defined as immunoreactivity in more than 10% of tumor cells. We also studied tumor proliferation (Ki-67 antigen), p53, and Her2 expression. Immunoreactivity was compared with disease-related survival. Univariate and multivariate analyses were performed.

Positive immunohistochemical clusterin expression was found in 25% of the tumors. On univariate analysis, clusterin immunoreactivity (P = 0.048), tumor stage (P = 0.011), nodal status (P = 0.0001), sex (P = 0.039), Ki-67 antigen index (P = 0.011), and Her2 expression (P = 0.020) were significantly associated with disease-related survival. On multivariate analysis, tumor stage (P = 0.01), nodal status (P = 0.0001), Ki-67 antigen (P = 0.0001), and Her2 expression (P = 0.001) were identified as significant independent predictive factors; clusterin expression missed the level of statistical significance by only a narrow margin (P = 0.058).

Although clusterin immunoreactivity showed only a trend towards an independent prognostic relevance in this study, we conclude that it may be used, in addition to conventional and other immunohistochemical prognosticators, as a supplementary tool to provide more prognostic information in patients undergoing cystectomy for muscle-invasive bladder cancer.