Secretion of Chromogranin A by Peptide-Producing Endocrine Neoplasms

TLDR

Chromogranin A, a protein co‑stored and co‑released with catecholamines from the adrenal medulla, has recently been identified in a variety of human endocrine tissues, both normal and neoplastic. The study investigated chromogranin A secretion by peptide hormone‑producing tumors in patients with pheochromocytoma, parathyroid adenoma, primary parathyroid hyperplasia, medullary thyroid carcinoma, thyroidal C‑cell hyperplasia, carcinoid tumor, oat‑cell lung carcinoma, pancreatic islet‑cell tumor, and aortic‑body tumor. Different forms of immunoreactive plasma chromogranin A were separated by size using gel filtration. All studied endocrine tumor groups exhibited elevated plasma chromogranin A, with 81 % sensitivity and 100 % specificity, whereas controls had normal levels, indicating that these tumors co‑release chromogranin A and that plasma measurement may aid diagnosis, especially in multiple endocrine neoplasia.

Abstract

Chromogranin A, the protein that is co-stored and co-released with catecholamines from the adrenal medulla, has recently been identified in a variety of human endocrine tissues, both normal and neoplastic. We investigated the secretion of chromogranin A by peptide hormone-producing human tumors in studies of patients with the following neoplastic disorders: pheochromocytoma, parathyroid adenoma, primary parathyroid hyperplasia, medullary thyroid carcinoma, thyroidal C-cell hyperplasia, carcinoid tumor, oat-cell lung carcinoma, pancreatic islet-cell tumor, and aortic-body tumor. All these patient groups had elevated concentrations of plasma chromogranin A. We distinguished different forms of immunoreactive plasma chromogranin A by size with the use of gel filtration. Plasma chromogranin A levels were not elevated in patients with diverse "control" conditions--both benign and malignant and both endocrine and nonendocrine--in which peptide hormones are not produced. The sensitivity and specificity of plasma chromogranin A elevations in the diagnosis of peptide-producing endocrine neoplasms were 81 and 100 percent, respectively. The elevation of plasma chromogranin A in our subjects suggests that their neoplasms co-release chromogranin A along with the usual resident hormone of the tumor, that these neoplasms could be characterized as "chromograninomas," and that measurement of plasma chromogranin A may be a useful diagnostic procedure in subjects with endocrine tumors, especially multiple endocrine neoplasia.