Chromogranin A (CgA) and its biomedical applications
Chromogranin A (CgA) and its biomedical applications, unveiling its structure-related functions
Chromogranin A (CgA) is an intrinsically disordered protein (IDP), first discovered in bovine adrenal medulla.
Under certain physiological conditions, CgA is cleaved into functionally diverse peptides (Vasostatin-1, Pancreastatin, Catestatin).
Chromogranin A (CgA) is widely released from endocrine, nervous, and digestive systems, functionally associated with circulatory, digestive, immune, metabolic, and nervous system.
CgA is cleaved when secreted, leaving the functional peptides having specific function.
CgA itself is 439aa + 18 signal peptide, but its functional peptides are diverse in sequence (cleavage sites).
Current Biomedical Application
The very first application of CgA was to detect neuroendocrine tumor (NET)
NET has mostly nonspecific symptoms (vomiting, pain) and five year overall survival rate drops significantly from 92% to 54% << early detection of NET is very crucial
- A pioneering study in 1986 demonstrated a sensitivity of 81% and a specificity of 100% for the diagnosis of pheochromocytoma.
- ELISA for detecting blood CgA concentration is used to confirm the existence of NET (79.9% of sensitivity and 97.7% of specificity)
Perspectives
- Diabetes
serum pancreastatin concentration – insulin resistance
- Microbiome dysbiosis
fetal concentration of CgA