The biological characteristics of chromogranin A and its role as a circulating marker in neuroendocrine tumours.

This paper reviews the biology of chromogranin A (CgA) and CgA-derived peptides and their possible role as markers for neuroendocrine tumours (NETs). NETs are neoplasms characterized by a low proliferation rate and, in some cases, a favourable prognosis. NETs often overproduce and release biologically active substances that are responsible for severe syndromes. The hormones and the biogenic amines released by biologically active NETs are currently used as biomarkers, but there is a need for sensitive markers for those NETs that are "biochemically silent". Circulating CgA levels have been demonstrated to be augmented in NET patients irrespective of the presence of syndromes related to hormone overproduction. Because of the high sensitivity and specificity of CgA, this glycoprotein can be successfully used in diagnosis, prognosis and follow-up of NETs. CgA blood evaluation seems of particular interest in the management of the gastroenteropancreatic tract NETs and in carcinoids.