Neuroendocrine Tumors

MARKER

The role of "markers" in the diagnosis / differential diagnosis of GEP-NET
1.	CHROMOGRANINs (CgA + CgB) in serum (primary vesicular - LDCV - large dense-core vesicles) CgA positiv in plasma in 94% (70-100%) CgB : pos. immunhistochemistry in benign insulinomas false positiv: renal failure, hepatic failure, atrophical gastritis, proton pump blocker therapy (gastrin), inflammatory bowel disease cleavage products of CgA:: Pancreastatin: inhibits insulin, glucagon, PTH, parietal cells, exocrine pancreas Vasostatin: suppresses vasoconstriction, PTH, stimulates cell adhesion Parastatin: inhibits PTH Chromostatin: inhibits catecholamines
2.	Synaptophysin (vesicular - SSV - small synaptic-like vesicles) Monoamine Transporters (vesiculär - VMAT-1, VMAT-2)
3.	Pancreatic Polypeptide (PP) : positiv in up to 74% of GEP-NET
4.	nuclear Ki67-expression, vascular - perineural invasion
5.	Neuron-specific enolase (NSE), cytosolic
6.	HCG-subunits, glycoproteins