{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Chromogranin A is a member of the chromogranin/secretogranin family of neuroendocrine secretory proteins. Examples of cells producing chromogranin A are the adrenal medulla, enterochromaffin-like cells and beta cells of the pancreas. The function of chromogranin A is unknown but it is a precursor to 3 functional peptides: vasostatin, pancreastatin and parastatin. These peptides negatively modulate the neuroendocrine function of the releasing cell (autocrine) or nearby cells (paracrine)."}]},{"type":"paragraph","children":[{"type":"text","value":"Chromogranin A is an excellent marker for Carcinoid Tumors, Pheochromocytomas, Paragangliomas, and other Neuroendocrine Tumors. Coexpression of chromogranin A and neuron-specific enolase (NSE) is common in neuroendocrine neoplasms. It has been identified in a wide variety of endocrine tissues including the pituitary, pancreas, hypothalamus, thymus, thyroid, intestine and parathyroid. It is generally accepted that the coexpression of certain keratins and chromogranin means neuroendocrine lineage. The presence of strong chromogranin staining and absence of keratin staining should raise the possibility of paraganglioma. Most pituitary adenomas and prolactinomas readily express chromogranin."}]}]}