Pancreatic neuroendocrine tumors: A review of serum biomarkers, staging, and management

Table 1 Pancreatic neuroendocrine tumors-associated hormonal syndromes and biomarkers

Tumor/syndrome	Location	Incidence (million per year)	Biomarker	Main symptoms
Insulinoma	Pancreas	1-32	Insulin	Hypoglycaemia
Gastrinoma	Pancreas, duodenum	0.5-21.5	Gastrin	Zollinger-Ellison syndrome: Gastroesophageal reflux and complicated peptic ulcer disease
VIPoma	Pancreas	0.05-0.2	Vasoactive intestinal peptide	Verner-Morrison syndrome: Watery diarrhea, hypokalemia, and achlorhydria
Glucagonoma	Pancreas	0.01-0.1	Glucagon	Necrotic migratory erythema, weight loss, hypoalbuminemia, and diabetes mellitus or impaired glucose tolerance
SSoma	Pancreas, duodenum, jejunum	Rare	Somatostatin	Hyperglycemia, cholelithiasis, and maldigestion of food
ACTHoma	Pancreas	Rare	ACTH	Cushing syndrome
GRHoma	Pancreas, lung, jejunum	Rare	GRH	Acromegaly
Carcinoid syndrome caused by pNET	Pancreas	Rare	Serotonin, 5-hydroxyindoleacitic acid	Skin flushing, diarrhoea, bronchospasm, and cardiac valve fibrosis
Hypercalcemia caused by pNET	Pancreas	Rare	Parathyroid hormone-related peptide	Hypercalcaemia and abdominal pain

pNETs: Pancreatic neuroendocrine tumors; ACTH: Adrenocorticotropic hormone; GRH: Growth hormone; SSoma: Somatostatin-producing NETs.