Biochemical Testing in Neuroendocrine Tumors.

Neuroendocrine cells are widely distributed throughout the body. They can produce, store, and secrete peptides and biogenic amines. Neuroendocrine tumors (NETs) are rare, but most are found in the intestine, pancreas, and lung. NETs may cause specific hormonal symptoms (eg, carcinoid syndrome) or appear nonfunctional. Blood or urine concentrations of tumor-secreted amines and peptides have been used as biomarkers in the diagnosis and management of NETs. This article focuses on currently available biochemical testing of blood or urine for gastroenteropancreatic and lung NETs and discusses the limitations of these tests and the potential role of newer multianalyte markers for NET management.