Abstract
OBJECTIVE: This study aimed to compare vitamin D receptor (VDR) immunoexpression in endometrial polyps and paired adjacent normal endometrium. METHODS: Seventeen women (mean age, 48 ± 9 years) undergoing hysteroscopic polypectomy were included. Paired samples of polyp tissue and adjacent normal endometrium were analyzed by standardized immunohistochemistry using an anti-VDR monoclonal antibody. Two blinded pathologists independently assessed staining intensity (0-3) and fraction of positive cells (0-2), and calculated a composite van Slooten score (0-6). VDR positivity was defined as a composite score ≥ 3. RESULTS: VDR expression was higher in polyps than in normal endometrium. Mean intensity (1.5 ± 1.1 vs. 0.8 ± 0.8; p = 0.041), fraction of stained cells (1.1 ± 0.7 vs. 0.4 ± 0.7; p = 0.020), and composite score (2.6 ± 2.0 vs. 1.0 ± 1.5; p = 0.020) were significantly greater in polyps. VDR positivity was observed in 58.8% (10/17) of polyps and 23.5% (4/17) of normal endometrial samples (p = 0.037). Interobserver agreement was substantial to almost perfect (κ = 0.70-0.85). No association was observed between VDR score and age, BMI, or menopausal status. CONCLUSIONS: Endometrial polyps exhibit increased VDR expression compared with paired normal endometrium. These exploratory findings suggest compensatory VDR upregulation in benign proliferative lesions, warranting confirmation in larger molecular studies.