Objectives. To determine whether the expression level of clusterin in transitional cell carcinoma (TCC) of the bladder could be used as a predictor of tumor recurrence and prognosis.

Methods. Total RNA samples were extracted from 89 specimens of TCC of the bladder, and the expression level of clusterin mRNA in these specimens was measured by Northern blot analysis. The results were evaluated with respect to several clinicopathologic factors.

Results. The mean level of clusterin mRNA expression in invasive TCC of the bladder was fourfold and fivefold higher than that in superficial TCC and normal urothelial tissue, respectively. The expression level of clusterin mRNA showed no significant correlation with sex, age, tumor size, or multiplicity, and the pathologic stage and tumor grade showed close associations with clusterin expression. The overall survival rate of patients with strong clusterin expression was significantly lower than that of patients with weak expression. Among the 43 patients with invasive TCC who underwent complete resection, the recurrence-free survival rate of patients with strong clusterin expression was significantly lower than that of patients with weak expression. Moreover, multivariate analyses indicated that among these 43 patients, strong expression of clusterin was an independent predictor of tumor recurrence.

Conclusions. These findings indicate that clusterin mRNA is strongly expressed in invasive TCC of the bladder compared with the expression in superficial TCC and that strong clusterin expression could be used as a novel predictor of prognosis of patients with TCC of the bladder.