Circulating Markers in Gastroenteropancreatic Neuroendocrine Tumors (GEP NETs)

Gastro-Entero-Pancreatic (GEP) NETs originate from both pancreatic islet cells or gastroenteric tissue (from diffuse neuroendocrine cells distributed throughout the gut) and are rare neoplasms, representing about 2% of all the gastrointestinal tumors. Due to their rarity, they are difficult to diagnose and the begnning of the diagnostic process is often based on the measurement of circulating markers, before planning expensive and invasive diagnostic tests (2, 3). A critical point is that the frequent late diagnosis of NETs is due to failure to identify symptoms or to establish the biochemical diagnosis; in fact 60-80% of NETs are metastatic at diagnosis. A prompt identification by the use of specific biomarkers is therefore useful to recognize these tumors (1).