NSE (neuron-specific enolase, ENO2) is a metalloenzyme involved in neural tissue development. In immunohistochemistry, NSE is a positive marker for neurons and neuroendocrine cells, and it is also positive in islets of Langerhans of the pancreas. In cancers, it is positive in neuroendocrine tumors such as carcinoid and schwannoma. NSE is a useful marker of disease status and prognosis in small-cell lung cancer, prostate cancer and acute lymphoblastic leukemia where elevated levels may indicate progression. References: Br J Cancer. 1994 Oct; 70(4): 759–761, PMID: 7917935; Int J Biol Markers. 2018 Jan;33(1):10-21, PMID: 28885659; Cell Physiol Biochem. 2018;46(4):1525-1535, PMID: 29689546; Int J Clin Exp Med. 2015; 8(6): 9498–9504, PMID: 26309614