[Chromogranin A: a marker of neuroendocrine tumors]

Chromogranins belong a unique family of secretory chromogranin and secretogranin proteins. They are present in the secretory vesicles throughout the neuroendocrine system. Chromogranin A is the major component. Its primary structure is well known but not yet its biological function. Chromogranin A performs as a prohormon which submits to processes of degradation. Active peptides are generated. Chromogranin A is a very used immunohistochemical marker. Reliable chromogranin A assays have been developed. In numerous studies it appear that the chromogranin A assay is reliable for the diagnosis and the follow-up of various endocrine tumors (principally the pheochromocytomas, neuroblastomas, gastrinomas and carcinoid tumors). The concentration of this general marker, in serum, reflects to the mass of the tumor. The chromogranin A levels will been interpreted in accordance to the localization of the primitive tumor, the existence of associated hormonal secretions and possible renal failure.