Chromogranin A belongs to the acidic, soluble protein present in the secretory vesicles of neuroendocrine.
Immunohistochemical studies have demonstrated that chromogranin A is present in virtually all granulecontaining
endocrine cells and in the great majority of tumors of neuroendocrine origin.
Molecular weight: 49 kD, 431 amino acid (32% glutamic acid) encoded on chromosome 14
Isoelectric point (PI): 4.75 – 4.68
Half-life: 18 minutes in circulation
- A very sensitive (83%) and highly specific (96%) diagnostic marker in the evaluation of actual or suspected pheochromocytoma. Drugs commonly employed in the diagnosis or treatment of pheochromocytoma has little effect on the plasma chromogranin A level.
- To ascertain the source of a tumor. A high chromogranin A level indicates that the tumor arises from neuroendocrine tissues.
- Endocrine tumors that do not produce their specific hormones, for example, calcitonin negative but chromogranin A positive C-cell carcinoma; zero-cell carcinoma; beta-cell carcinoma; parathyroid carcinoma.