A Critical Approach to Clinical Biochemistry of Chromogranin A

Chromogranin A (CGA) is a member of the granin family of proteins which are widespread in endocrine, neuroendocrine, peripheral, and central nervous tissues, where they are typically found in secretory granules. It is well accepted that CGA cooperates to regulate synthesis and secretion of these various granule signaling molecules.Because of its ubiquitous distribution within neuroendocrine tissues, CGA can be a useful diagnostic marker for neuroendocrine neoplasms, including carcinoids, pheochromocytomas, neuroblastomas, medullary thyroid carcinomas (MTC), some pituitary tumors, functioning and nonfunctioning islet cell tumors and other amine precursor uptake and decarboxylation (APUD) tumors. It is also useful as a prognostic marker for detection of recurrence and monitoring of response to different treatments. As other tumor markers, it is imperative to know its physiology and pathophysiology, its sensitivity and specificity in different neuroendocrine tumors (NETs), and carefully integrate these data with the clinical data of the single patient, to maximize its diagnostic/prognostic index.