1,25 Dihydroxyvitamin D(3) receptor expression in superficial transitional cell carcinoma of the bladder: a possible prognostic factor?

Objective: Vitamin D receptors (VDR) have been detected in normal tissues and in a number of cancer types. This study was undertaken to determine the VDR expression status and to elucidate the prognostic significance of VDRs in superficial transitional cell carcinoma (TCC) of the human bladder.

Methods: VDR expression was investigated in the tumour tissue blocks which were obtained by transurethral resection from 105 patients with superficial TCC without concomitant carcinoma in situ and in 30 control subjects. Median follow-up of the patients was 40 months. The expression of nuclear VDR was evaluated immunohistochemically using avidin-biotin-peroxidase method and a monoclonal VDR antibody. VDR staining intensity in samples were assessed semi-quantitatively and graded as [-] if VDR was lacking, [+] if <33% of cells were stained, [++] if 33-66% of cells and [+++] if >66% were stained. Staining characteristics were compared with the clinico-pathologic results.

Results: VDRs were detected in 85.7% of the patients with superficial TCC and in 66.6% of the controls (p = 0.02). No correlation was found between VDR expression and pathological stage and grade (p = 0.05 and p = 0.09, respectively). Progression in pathologic stage was significantly higher in VDR[+++] tumours (p = 0.001). Also, disease-free survival was significantly lower and tumour size was significantly greater in VDR [+++] tumours than [-], [+] and [++] ones (p = 0.02, p = 0.008 and 0.007, respectively). No significant difference was found between patient age, sex, tumour multiplicity in terms of VDR expression. Survival was not affected by VDR expression. In multivariate analysis VDR expression was not found to be an independent prognostic factor.

Conclusion: Superficial TCC of the bladder express VDRs. The association of increased VDR expression and higher disease progression may be useful in discriminating less differentiated superficial TCCs with poor outcome.