Fol. Biol. 2011, 57, 173-181
Chromogranin A in Physiology and Oncology
Chromogranin A (CgA) is a hydrophilic acidic one-chain peptide containing 439 amino acids, preceded by NH2-terminal 18-amino-acid signal peptide; the complete pre-chromogranin A molecule thus encompasses 457 amino acids. It is a member of the chromogranin family that comprises several proteins. The CgA gene is a single-copy gene localized in the locus 14q32. Chromogranin A is produced by endocrine and neuroendocrine cells. The largest amount of CgA occurs in chromaffin granules of adrenal medulla and in the dense-core vesicles of sympathetic nerves. Its biological functions have not been completely elucidated, but it is known that it acts as a precursor of many biologically active peptides generated by cleavage at specific sites. It is the major soluble protein co-stored and co-released along with resident catecholamines and polypeptide hormones or cell-specific neurotransmitters. Because of its widespread distribution in neuroendocrine tissue, it can be used both as immunohistochemical marker and serum marker of neuroendocrine tumours. CgA has been used as a rather reliable tumour marker because its level is significantly increased in neuroendocrine tumours and changes of its level reflect the tumour response to therapy or tumour recurrence.
Keywords
chromogranin, neuroendocrine tumours, cleavage fragments, extracellular functions, intracellular functions, tumour marker.
Funding
The article is supported by the research project MSMT 0021620808 from the Ministry of Education, Youth and Sports of the Czech Republic.
References
Copyright
This is an open-access article distributed under the terms of the Creative Commons Attribution License.
