TY - CHAP M1 - Book, Section TI - Pancreatic Neuroendocrine Tumors A1 - Melcescu, Eugen A1 - Koch, Christian A. A2 - Murray, Michael F. A2 - Babyatsky, Mark W. A2 - Giovanni, Monica A. A2 - Alkuraya, Fowzan S. A2 - Stewart, Douglas R. PY - 2014 T2 - Clinical Genomics: Practical Applications in Adult Patient Care AB - Disease summary:Pancreatic neuroendocrine tumors (PNETs) are uncommon and represent only 1% to 2% of pancreatic neoplasms, about 85% of these tumors occur in the pancreas and 15% are extrapancreatic tumors.Based on their clinical expression these tumors are categorized as either functional or nonfunctional.Functional tumors (~50%) are characterized by abnormal secretion of (often) biologically active peptides mostly insulin, gastrin, glucagon, somatostatin, or vasoactive intestinal polypeptide (VIP).Nonfunctional tumors are clinically silent although they can secrete neurotensin, pancreatic polypeptide or chromogranin A (CgA), but these peptide-like substances are not biologically active. Most nonfunctional PNETs have a malignant course. They are discovered usually when their size is large, have already invaded adjacent organs or metastasized.Among functional tumors, insulinomas and gastrinomas account for 25% and 15% of the cases, respectively. The other functional PNETs are responsible for the remaining 15%.Negative prognostic factors for PNETs are considered: metastasis, tumor diameter, angioinvasion, proliferative index Ki-67, lymph nodes, and mitoses. Localized disease has a 5-year survival rate of 60% to 100%, whereas regional and metastatic PNETs have a 40% and 29% survival rate, respectively. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/10/09 UR - accessbiomedicalscience.mhmedical.com/content.aspx?aid=1102700667 ER -