Presence of 1,25-dihydroxy vitamin D receptor in normal and abnormal breast tissue

We have demonstrated that a variety of cultured breast cancer cell lines, human breast cancers, non-malignant breast tumours and normal rabbit breast tissue contain specific, high-affinity, low-capacity receptors for 1,25-(OH)2D3. Considered with the ability of normal breast tissue to transport calcium from blood into breast milk, which has recently been shown to be stimulated by 1,25-(OH)2D3, the presence of this receptor could explain the high incidence of hypercalcaemia in this common disease and has important implications for the management of metastatic breast cancer. Finally these findings suggest that breast is a normal target organ for 1,25-(OH)2D3 action.