CYP24A1 Overexpression and Vitamin D Deficiency: A Potential Prognostic Axis in Thyroid Nodules Classified by the Bethesda System.

INTRODUCTION: Vitamin D, crucial for calcium balance and bone health, also regulates the cell cycle and has anti-tumour properties. Given the rising incidence of thyroid cancer, this study investigates the association between preoperative vitamin D levels and CYP24A1 mRNA expression in thyroid nodules (TNs) classified by the Bethesda system. METHODS: A prospective observational study included 40 adults with TNs. Exclusion criteria applied. Clinical evaluation involved blood tests, thyroid ultrasound, fine-needle aspiration cytology, and histopathology. Serum vitamin D, calcium, and CYP24A1 mRNA expression were analysed for correlations. RESULTS: Participants had a mean age of 37.3 years; 75% were female. Thyroid Imaging Reporting and Data System (TIRADS) identified suspicious nodules. Most patients (95%) had normal thyroid-stimulating hormone levels, but 52.5% showed vitamin D deficiency, and 47.5% had low calcium levels. CYP24A1 mRNA expression was elevated, especially in papillary thyroid carcinoma (PTC). Positive correlations were found between vitamin D, calcium, and CYP24A1 expression. CONCLUSION: The study highlights the role of vitamin D deficiency and elevated CYP24A1 expression in TNs, particularly PTC. TIRADS and Bethesda classifications remain valuable diagnostic tools. CYP24A1 may serve as a prognostic marker or therapeutic target, suggesting the need for further research into vitamin D pathways in thyroid disease.