Detection of a Mr 24,000 estrogen-regulated protein in human breast cancer by monoclonal antibodies.

Monoclonal antibodies have been prepared that can specifically detect an estrogen-regulated protein with a molecular weight of 24,000 in the MCF-7 human breast tumor cell line and in human breast tumor biopsies. These antibodies are of the immunoglobulin G1 subclass, exhibit a high affinity for the Mr 24,000 protein, and recognize an antigenic site that is stable to sodium dodecyl sulfate gel electrophoresis and electrophoretic transfer techniques. These monoclonal antibodies have been used to confirm estrogen regulation of the Mr 24,000 protein in MCF-7 cells and to detect Mr 24,000 protein in certain human breast tumors.