NORMAL AND MALIGNANT BREAST TISSUE IS A TARGET ORGAN FOR 1, 25‐(OH)2 VITAMIN D3

Abstract

Malignant and benign human breast tumors and rabbit breast tissue were examined for specific receptors for 1,25-dihydroxyvitamin D3 using competitive binding studies and sucrose density gradient analysis. Classical high affinity, low capacity receptors for 1,25-dihydroxyvitamin D3 were found in breast and node tissue in 7 of 10 patients with breast cancer and in all 3 patients with benign neoplasms. An inflammatory breast mass showed no binding. Similar receptors were found in breast tissue from pregnant and lactating rabbits. 1,25-Dihydroxyvitamin D3 may activate Ca transport in the malignant as well as in the normal lactating breast.