Immunohistochemical Expression of Vitamin D receptor in Breast Cancer in Erbil city

Background & objectives: Vitamin D receptor is a nuclear receptor that modulates the activity of genes. The purpose of this study was to evaluate the frequency of vitamin D receptor expression in breast carcinoma by immunohistochemistry and to investigate the association between vitamin D receptor expression with some clinicopathologic factors, like tumor grading, staging, histologic type (ductal and non-ductal) and the hormonal status. Methods: One hundred formalin-fixed paraffin embedded tissue blocks of mastectomy and core biopsy specimens diagnosed as carcinoma, were obtained from a private laboratory in Erbil city/Iraq from October 2020-October 2022. In this study, vitamin D antibody (a mouse monoclonal antibody) was applied to a breast cancer tissue samples and its expression was assessed. Results: Nuclear vitamin D receptor was expressed in 32% of the cases, and a strong relation was noted between vitamin D receptor expression and low-grade tumor (p = 0.034), estrogen receptor (p-value =0.007), and progesterone receptor (p = 0.045) positivity, while no significant association was noted between vitamin D receptor expression and other clinicopathologic parameters like age, lymph node status, tumor stage, the type of the cancer and human epidermal growth factor receptor 2 status. Conclusion: increased Vitamin D receptor expression in breast tumors appears to be associated with a better prognosis. Vitamin D receptor expressed in one third of cases in which there was significant association with tumor grade and hormonal receptors.