RT Journal Article SR Electronic T1 Vitamin D Status and Breast Cancer Risk JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 2573 OP 2580 VO 26 IS 4A A1 KAY W. COLSTON A1 LORRAINE C. LOWE A1 JANINE L. MANSI A1 MORAY J. CAMPBELL YR 2006 UL http://ar.iiarjournals.org/content/26/4A/2573.abstract AB Background: Local synthesis of 1α,25(OH)D3 in breast tissue may contribute to maintenance of normal cell function and could be impaired with low circulating levels of the precursor 25hydroxyvitamin D. The aims of this study were to: i) assess the association between breast cancer risk and plasma 25OHD3 concentration and ii) define the significance of expression of the 25OHD activating enzyme CYP27b1 in non-malignant and malignant models of breast epithelial cells. Materials and Methods: Breast cancer patients and control women were recruited and their 25OHD levels measured by enzyme-linked immunosorbent assay (ELISA). MRNA expression of CYP271b and the 1,25(OH)2D3 inactivating enzyme CYP24 were measured in breast cancer cell lines by RT-PCR and correlated with immunoblotting approaches to the translated proteins. Results: For women with 25OHD <50 nM the odds ratio for breast cancer compared with women with 25OHD >50 nM was 3.54 (CI 1.89-6.61, p<0.001). CYP271b and CYP24 were detected in non-malignant and malignant cell models. Protein levels of 24OHase but not 1αOHase were decreased at confluence in the cell lines. Conclusion: Impaired local generation of 1,25OHD3 may contribute to the development of breast cancer. Copyright© 2006 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved