Flashcards in 245b neuroendocrine tumors Deck (11):
neuroendocrine tumors - source? secrete anything? receptors? stain?
have granules that can secrete hormones and amines
functional (give syndrome) and non-functional
somatostatin receptors + other markers
chromogranin A (CgA) - monitor for treatment response
pancreatic neuroendocrine tumors - what peptides can be produced?
glucagon, insulin, somatostatin, pancreatic polypeptide, serotonin + ecotpopic hormones
50% don't product anything
carcinoid syndrome (first aid)
Rare syndrome caused by carcinoid tumors (neuroendocrine cells), especially metastatic small bowel tumors, which secrete high levels of serotonin (5-HT).
Not seen if tumor is limited to GI tract (5-HT undergoes first-pass metabolism in liver). Results in recurrent diarrhea, cutaneous flushing, asthmatic wheezing, and right-sided valvular disease.
increased 5-hydroxyindoleacetic acid (5-HIAA) in urine, niacin deficiency (pellagra).
Treatment: resection, somatostatin analog (octreotide)
rule of 1/ 3rds
1/3 present with 2nd malignnacy
1/3 are multiple
most common malignancy in small intestine
when do most NET become symptomatic?
Zollinger-Ellison syndrome (first aid)
Gastrin-secreting tumor of pancreas or duodenum. Acid hypersecretion causes recurrent ulcers in distal duodenum and jejunum.
Presents with abdominal pain (peptic ulcer disease, distal ulcers), diarrhea (malabsorption). May be associated with MEN 1.
Insulinoma (first aid)
Tumor of " cells of pancreas --> overproduction of insulin --> hypoglycemia.
Whipple triad of episodic CNS symptoms: lethargy, syncope, and diplopia.
Symptomatic patients have decreased blood glucose and increased C-peptide levels (vs. exogenous insulin use).
Treatment: surgical resection.
imaging studies with NETs
somatostatin-receptor --> octreoscan
somatostatin - function? drug use? drug?
bioactive neuropeptide --> inhibitors effects throughout body including GI tract --> blocks gastric acid, amylase; anti-inhibitory
ocretoride prolongs life
drug is octreotide (longer half life)
somatostatin receptors - type of receptors? functions?
antisecretory, antiproliferative, apoptotic effects
mTOR - role? drug? cancer rx?
central role in proliferation pathways in cancers to include cell growth, angiogenesis, protein synthesis
downstream of signaling that is deregulated in cancer so good target
drug: everolimus --I mTOR
good for insulinoma and NETs