Clusterin immunoreactivity as a predictive factor for progression of non-muscle-invasive bladder carcinoma

There is a need for prognostic markers which can predict the subset of patients who will not respond sufficiently to conservative management in non-muscle-invasive bladder carcinoma. We analyzed the association of clusterin (CLU) with clinicopathological factors.

Immunohistochemical CLU expression was investigated in paraffin-embedded archival tissues of initial transurethral resection specimens of 46 patients with non-muscle-invasive bladder carcinoma. The result was expressed as the proportion of the number of CLU-containing tumor cells to the total number of tumor cells detected in each slide and 'percent CLU expression' was calculated for each patient.

Of the 46 cases (35 male, 11 female), 18 were ≥ 65 years of age. CLU expression was significantly higher in male and elderly patients. Following the initial transurethral resection, 39 patients showed tumor recurrence, and progression was seen in 25 patients, of whom 17 progressed to muscle invasion during follow-up. Although there was no significant correlation between CLU expression and recurrence, significant correlation with overall progression and progression to muscle-invasive disease was observed in this cohort of patients (p = 0.001 and p = 0.014, respectively). Among the patients with progression to muscle invasion, 13 underwent radical cystectomy with pT2 tumor in 5 patients in the final pathology of surgical specimens and pT3 and higher in the remainder.

CLU immunoreactivity showed correlation with age, gender and progression, mainly progression to muscle invasion. Thus, CLU can be used as a molecular marker to predict the potential of progression to muscle-invasive disease in a particular tumor which in turn may prove useful in the decision-making process for early cystectomy without losing time with conservative management.