Isolated ectopic production of the free beta subunit of chorionic gonadotropin by an epidermoid carcinoma of unknown primary site

Abstract

Metastatic choriocarcinoma was suspected in a 39‐year‐old woman who presented 7 months postpartum with fatigue, pelvic pain, a massive pleural effusion, and a positive urine pregnancy test. Subsequent evaluation resulted in discovery of the isolated production of the freeβ‐subunit of chorionic gonadotropin (CG‐β) by a widespread, poorly differentiated epidermoid carcinoma. Chemotherapy was ineffective, the woman died, and at autopsy the primary site of the tumor could not be determined. The patient's serum (185 ng/ml) and a tumor metastasis (720 ng/g) contained large amounts of immunoactive material that diluted in parallel to CG‐β standard, but neither chorionic gonadotropin (CG), its alpha subunit, nor other placental proteins were detected. A monoclonal antibody that recognizes free CG‐β, but not intact CG, was instrumental in implicating an ectopic source of the CG‐β before a tissue diagnosis was obtained. When the patient's serum was chromatographed on a dextran gel, the CG‐β immunoactivity eluted in a position of higher apparent molecular weight than either standard CG or CG‐β, suggesting that this neoplasm secreted an altered molecular form of the CG‐β subunit.

Immunohistochemical study of the expression of human chorionic gonadotropin-? in oral squamous cell carcinoma

“…It is a glycoprotein hormone comprised of noncovalently linked ␣ and ␤ subunits. [3][4][5] Although the ␣ subunit is shared by other glycoprotein hormones such as luteinizing hormone, follicle-stimulating hormone, and thyroid-stimulating hormone, the ␤ subunits are unique for each hormone. [6][7][8] hCG is secreted by placental syncytiotrophoblasts and in elevated amounts by neoplastic cells in tumors of trophoblastic origin.…”

A novel form of ectopic human chorionic gonadotrophin β-subunit in the serum of a woman with epidermoid cancer

“…We recently studied a woman whose poorly differentiated epidermoid carcinoma of unknown origin appeared to be an ectopie source of free hCGß subunit without detectable subunit or intact hCG (Nagelberg, Marmorstein, Khazaeli & Rosen, 1985). When an aliquot of her serum was gel chromatographed, the hCGß immunoactivity eluted in a posi¬ tion of higher apparent molecular weight than standard hCGß.…”