Purpose: The active form of vitamin D3, that is 1α,25-dihydroxyvitamin D3, binds with vitamin D receptor, which forms a complex with retinoid X receptors α, β and γ to manifest antitumor effects. We examined the expression of vitamin D receptor and retinoid X receptors in renal cell carcinoma and elucidated the prognostic significance of these receptors. Materials and Methods: We performed immunohistochemical examination of vitamin D receptor, and retinoid X receptors α, β and γ in nephrectomized specimens of 68 patients with renal cell carcinoma. We analyzed the correlation between the expression of these receptors and clinicopathological parameters or patient survival. Mean followup was 68.2 months. Results: No significant correlation was found between the expression of vitamin D receptor, retinoid X receptor α or β and clinicopathological parameters. In contrast, retinoid X receptor γ expression correlated significantly with tumor stage (p = 0.009) and distant metastasis (p = 0.005). The 5-year cancer specific survival rate was higher in patients with retinoid X receptor γ positive renal cell carcinoma than those with retinoid X receptor γ negative renal cell carcinoma (79.3% vs 40.0%, p <0.05). Cox regression analysis revealed that retinoid X receptor γ expression, tumor status and lymph node status were significant independent prognostic factors in patients with renal cell carcinoma (p <0.05). A significant correlation was observed between the expression of retinoid X receptor γ and tumor stage, distant metastasis or the 5-year cancer specific survival rate. Furthermore, retinoid X receptor γ expression was an independent prognostic factor in patients with renal cell carcinoma. Conclusions: Our observations suggest that alterations of vitamin D receptor and retinoid X receptor expression may be involved in renal carcinogenesis and retinoid X receptor γ expression may be a useful prognostic marker in patients with renal cell carcinoma.
- renal cell
- retinoid X receptors