Ki67 tumor expression in breast cancer post-menopausal patients following calcitriol supplementation

14612 Background: Breast cancer patients present lower 1,25(OH)2D3 or 25(OH)D3 serum levels than unaffected women. Although breast cancer cell lines are growth inhibited by to vitamin D supra-physiological concentrations, there is much uncertainty about the anti- proliferative effect of physiological concentrations of 1,25(OH)2D3, the active form of vitamin D, in human beings. Vitamin D supplementation to post-menopausal women may be indicated to reduce bone loss. Methods: We have evaluated tumor dimension, proliferation rate (Ki67 expression), 1,25(OH)2D3 serum concentration, before and after a one month calcitriol supplementation (dose to prevent osteoporosis) to post-menopausal patients. Twenty one patients with clinical stage II disease, signed the informed consent and took part in the study from Jan- Nov 2007. Median age was 56 years (50–66), all tumors were grade 2/3, ER was detected in 11/18 and HER2 in 8/18 tumors; two tumors were triple negative. The first 10 (group-GI) and the next 11 patients (...