Human chorionic gonadotropin as a tumor marker.

Ectopic production and secretion of hormones by a wide variety of tumors has been known for decades. Initially, ectopic hormone secretion was recognized by signs and symptoms of excess circulating biologically active hormone. With development of more sophisticated assay techniques, biologically inactive fragments and "big" forms of authentic hormones have been identified in these syndromes. Recently, a specific hCG assay has been developed for selectively measuring hCG in plasma samples containing both hLH and hCG. Studies reported to date suggest that hCG may be a good tumor marker. Using that assay system, several hundred sera obtained from patients with a wide variety of tumors were screened. Patients with tumors of the stomach, liver, ovary and testis were found to have the highest incidence of ectopic hCG secretion.