Chromogranin A, also known as parathyroid secretory protein 1, or CGA is a secretory protein and a member of the granin family. In humans it is encoded by the gene, CHGA. It is translated as a ~460 amino acid protein of mass 70-85 kDa, but it can be further processed into smaller biologically active neuroendocrine peptides, pancreastatin, catestatin, parastatin, vasostatin I and vasostatin II. Chromogranin A is a well characterized cancer biomarker and is elevated in adrenal and gastrointestinal neuroendocrine tumors. Antibodies to CgA can be a useful tool in the investigation of cancer.