SCGN (Secretagogin) is a secreted calcium-binding protein found in the cytoplasm. It is related to calbindin D-28K and calretinin. It is thought to function in KCL-stimulated calcium flux and cell proliferation. SCGN is overexpressed in a number of neuroendocrine-derived cancers, including those arising from the pancreas, lung, prostate, adrenal and pituitary glands and the colon. In small cell lung cancer, SCGN has been found to suppress apoptosis and increase resistance to chemotherapy, and may be a predictive marker for response to therapy. In immunohistochemistry of normal tissue, SCGN has cytoplasmic and nuclear positivity in enteroendocrine cells, in the molecular cell layer of the cerebellum, and in islets of Langerhans. References: Oncotarget. 2014 Sep; 5(17): 7760–7775, PMID: 25226615; J Biol Chem. 2000 Sep. 275 (32): 24740–51, PMID: 10811645