Vitamin D receptor gene expression in HPV-negative oral carcinomas – limited prognostic value within a complex molecular network

Abstract

Introduction/Objective The vitamin D receptor (VDR) regulates cell proliferation, differentiation, apoptosis, and immune responses and has been proposed as a potential cancer biomarker. This study investigated VDR gene expression in oral squamous cell carcinoma (OSCC), an aggressive malignancy with unfavorable outcomes, particularly in HPV-negative tumors.

Methods VDR mRNA expression was analyzed by reverse transcription quantitative PCR in tumor samples from 109 HPV-negative OSCC patients, and relative expression was calculated by the 2^(−ΔΔCt) method. Associations with clinicopathological variables were assessed using χ² and Fisher’s exact tests, while survival was evaluated by Kaplan–Meier and Cox regression analyses.

Results VDR expression was not significantly associated with clinicopathological characteristics. Although patients with low VDR expression showed longer overall survival than those with high expression, the difference was not significant (p = 0.253). Borderline associations were observed in early survival, with the 24-month landmark analysis (p = 0.050) and among patients with recurrent tumors (p = 0.051). VDR expression was not an independent prognostic factor.

Conclusion VDR gene expression alone has limited prognostic value in HPV-negative OSCC. However, the observed borderline associations with short-term survival and among patients with recurrent tumors suggest a potential context-dependent role in disease progression that warrants further investigation.

Keywords: oral carcinoma; vitamin D receptor; VDR; gene expression