Stains & CD markers

Editorial Board Members: Raul S. Gonzalez, M.D., Kelly Magliocca, D.D.S., M.P.H., Maria Martinez-Lage, M.D., Brandon Umphress, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Robert Terlević, M.D.
Semir Vranić, M.D., Ph.D.

Last author update: 3 November 2022
Last staff update: 3 November 2022

Copyright: 2019-2023,, Inc.

PubMed Search: SSTR2A

Robert Terlević, M.D.
Semir Vranić, M.D., Ph.D.
Page views in 2022: 4,435
Page views in 2023 to date: 4,725
Cite this page: Terlević R, Vranić S. SSTR2A. website. Accessed September 27th, 2023.
Definition / general
  • Somatostatin receptor 2a
  • 1 of 5 types 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 growth factor secretion 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)
  • SSTR2 expression in nasopharyngeal cancer is induced by the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) via the NFκB pathway (Nat Commun 2021;12:117)
Clinical features
  • 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. Neuroendocrine breast cancer
  4. Oligodendroglioma
  5. Small cell lung cancer
Board review style answer #1
A. Grade I neuroendocrine tumor of the small intestine

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Reference: SSTR2A
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