Background and aim: In recent years, there has been considerable interest in hether vitamin D inhibits breast cancer development. Experimental studies have shown that vitamin D promotes cell differentiation and retards or terminates proliferation of breast cancer cells. However, there is little evidence supporting the association of vitamin D and prognosis of breast cancer. Methods and Materials: In this analytic-descriptivestudy, 119 female patients with histological proven breast cancer were recruited in Tabriz oncology clinics in a 15-month period of time. History of chemotherapy, radiotherapy or receiving vitamin D/Ca supplements and presence of other malignancies were exclusion criteria. Serum level of 25 hydroxy vitamin D (25(OH)D) was measured in all patients.
Results: One hundred and nineteen patients with a mean age of 50.4±12.6 (26-76) years were enrolled in the study. Metastasis was present in 21.8% of the cases. Stage of tumor was I, II, III and IV in 11, 56, 26 and 26 patients, respectively. The Tumor grade was low in 37 cases, intermediate in 46 cases, and high in 36 cases. The P53, Ki-67, HER2, ER and PR were positive in 30.3%, 49.6%, 17.6%, 61.2% and 55.5% of the patients, respectively. The mean serum level of 25(OH)D was 15.7±17.8 (4-122) ng/ml, deficient in 66 cases, insufficient in 36 cases and normal level in 17 cases. The median level of 25(OH)D was lower in the P53+ group in a borderline trend (17.3 vs. 13.6 ng/ml; p=0.07). The median level of 25(OH)D was significantly higher in the patients with metastasis, as well (27.7 vs. 12.0 ng/ml; p=0.03). There was no significant association between the serum level of 25(OH)D and other studied parameters.
Conclusion: Based on our findings, there may be an association between the serum level of 25(OH)D and prognosis of breast cancer.