Ectopic human chorionic gonadotropin in breast carcinoma.

Immunoreactive human chorionic gonadotropin (hCG) was found in 9 of 65 surgically removed malignant breast tumors. Concentrations ranged from 5 to greater than 500 mIU hCG/g tumor. hCG was measured by a beta-chain specific readiommunoassay. In further study of these specimens, an immunoperoxidase staining technique was used to stain for hCG in formalin-fixed sections. The hCG was shown to be localized within the cytoplasm and on the surface of the malignant cells.