Topic Completed: 18 March 2019

Minor changes: 31 August 2020

Copyright: 2019-2020,, Inc.

PubMed Search: SSTR2A [title]

Robert Terlević, M.D.
Semir Vranić, M.D., Ph.D.
Page views in 2019: 1,033
Page views in 2020 to date: 1,375
Cite this page: Terlević R, Vranić S. SSTR2A. website. Accessed September 23rd, 2020.
Definition / general
  • Somatostatin receptor 2a
  • One of 5 members of somatostatin receptors
Essential features
  • Transmembrane G protein coupled receptor widely distributed in normal human tissues
  • Mediates antisecretory effects of somatostatin by inhibiting high voltage activated calcium channels (FEBS Lett 1994;355:117)
  • Mediates antiproliferative effect in tumors via direct and indirect mechanisms
  • Direct mechanisms include promotion of apoptosis via upregulation of Bax, inhibition of growth factor action on tumor cells via inhibition of MAPK phosphorylation and cell cycle arrest (Front Neuroendocrinol 2013;34:228)
  • Indirect mechanisms include inhibition of secretion of growth factors and antiangiogenic effects via upregulation of potent angiogenic inhibitor thrombospondin-1 in pancreatic tumors, inhibition of secretion of VEGF, PDGF, IGF1 by endothelium and monocytes (Proc Natl Acad Sci U S A 2009;106:17769, Mol Endocrinol 2005;19:255)
Clinical features
  • Mediates the antisecretory effect of somatostatin analogues in growth hormone secreting pituitary adenomas and hormone secreting neuroendocrine tumors of the gastrointestinal tract (Front Neuroendocrinol 2013;34:228)
  • Membranous and cytoplasmic staining
Uses by pathologists
Prognostic factors
Microscopic (histologic) description
  • Staining intensity usually variable
Microscopic (histologic) images

Contributed by Robert Terlević, M.D.

Neuroendocrine breast carcinoma

Positive staining - normal
Positive staining - disease
Negative staining
Board review style question #1
    Which of the following tumors is most likely to stain with SSTR2A?

  1. Grade I neuroendocrine tumor of the small intestine
  2. Grade II neuroendocrine tumor of the pancreas
  3. Small cell lung cancer
  4. Oligodendroglioma
  5. Neuroendocrine breast carcinoma
Board review answer #1
A. Grade I neuroendocrine tumor of the small intestine

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