Chromogranin A

Chromogranin A (CgA) is the most important member of the granin family. It is stored with hormones and neurotransmitters in large dense core vesicles or chromaffin granules and together with them it is released constitutively or in a controlled way. In this review are presented the role of CgA and biologically active peptides derived from it, as well as its use as a marker of certain diseases. CgA plays a significant role in sectorial granulogenesis (sorting and processing of secretory protein content, maturation and condensation of secretory granules) and maintaining calcium homeostasis. Glycosylation, phosphorylation, sulfation, and/or proteolytic processing of CgA results in biologically active peptides that exhibit hormonal, autocrine, and paracrine activity. In the cardiovascular, metabolic, immune and diffuse neuroendocrine system, CgA and biologically active peptides derived from it have numerous, sometimes conflicting roles. CgA has been identified as an important immunohistochemical tumor marker of neuroendocrine tumors, prostate cancer and microcellular lung cancer with neuroendocrine differentiation. Its credibility is conditioned by the tumor itself (localization, size, density of secretory granules and secretory activity), dissemination of the tumor and application of the diagnostic technique. Elevated CgA values cannot be used to assess the progression of tumors that are not of neuroendocrine origin. In chronic heart failure and acute coronary syndrome, CgA is an independent prognostic factor of the disease.