CGA and neoplasm: CgA itself can also be degraded into a series of smaller biologically active peptides, such as pancreastatin, catestatin, and vasostatins I and II.1 Recently, the newest NEN classification systems such as World Health Organization (WHO) 2010 classification, European Neuroendocrine Tumor Society (ENETS) and the North American Neuroendocrine Tumor Society report that immunohistochemical (IHC) detection of CgA should be performed to confirm the ‘neuroendocrine’ character of tumor cells.2–4 CgA is also used as a circulating marker.