Expression of Vitamin D Receptor (VDR) in Urinary Bladder Carcinoma: Immunohistochemical and Histopathological Study

Abstract

Background: Bladder cancer is the most common malignancy of the urinary tract. Calcitriol [1,25 (OH)₂vitamin D3] has anticancer effects mediated through binding to vitamin D receptor (VDR). The expression of VDR is present in many normal and cancer tissues. But, there is little information about its expression in urinary bladder carcinoma. This study aimed to analyze VDR immunohistochemical expression in 74 Egyptian patients with urinary bladder carcinoma and to evaluate its association with different clinicopathological parameters.
Methods: Sections from formalin-fixed, paraffin-embedded tumor blocks were stained immunohistochemically using monoclonal anti-VDR antibody. VDR protein expression as well as its immunostaining patterns were recorded and scored separately in each case using semi-quantitative immunoreactive score.
Results: VDR was consistently expressed in the included histologically normal urothelium while tumor cells showed variable degrees of expression. Cytoplasmic/membranous VDR expression was common among the studied cases especially those with urothelial morphology (p = 0.076). While, the mean nuclear VDR was significantly (p = 0.007) higher in non-urothelial tumors. Nuclear VDR was significantly associated with muscle invasion (p = 0.000) and tumor stage (p = 0.001) in urothelial carcinoma. It was also statistically related to tumor grade, stage and muscle invasion in non-urothelial tumors (p = 0.002, 0.003 and 0.012, respectively).
Conclusion: there was a significant relation between nuclear VDR expression and prognostic markers suggesting its decrease as an indicator of a poorer prognosis. Vitamin D supplementation may represent a new treatment option for patients with bladder cancer.