Ectopic Production of the Isolated Alpha Subunit of the Glycoprotein Hormones

Abstract

Serum and tumor extract from a 27-year-old woman with metastatic gastric carcinoid contained high concentrations (20,000 ng per milliliter and 180,000 ng per gram) of a material ("alpha") resembling the alpha subunit of glycoprotein tropic hormones in immunologic, gel Chromatographic and biologic properties. Ectopic production of "alpha" was isolated and not accompanied by comparable amounts of a beta subunit or a complete glycoprotein hormone. The tumor also contained high concentrations of parathyroid hormone and calcitonin. Radioimmunoassay of serums from other patients with cancer (three of 24 patients with the carcinoid syndrome and three of 106 with bronchogenic carcinoma) revealed increased concentrations of "alpha" as compared to 106 controls without cancer. The alpha subunit of glycoprotein tropic hormones may be a quantitative marker of neoplasia in certain cases of cancer. (N Engl J Med 290:1441–1447, 1974)