Somatostatin and dopamine receptor profile of gastroenteropancreatic neuroendocrine tumors: an immunohistochemical study

Endocr Pathol. 2011 Mar;22(1):24-30. doi: 10.1007/s12022-011-9149-8.

Abstract

Somatostatin and its synthetic analogs act through five specific somatostatin receptors (sstr1-5), found on the cell membrane of various tumors, including endocrine ones. Dopamine--a known neurotransmitter--acts through five membranous dopamine receptors (D1R-D5R) which have recently been found to be expressed in endocrine tumors. We evaluated the immunohistochemical expression of the sstrs and D2R in a large series of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A total of 22 (28.94%) well-differentiated NETs (WDNETs), 6 (7.89%) WDNETs of uncertain biology, 26 (34.21%) well-differentiated neuroendocrine carcinomas, and 22 (28.94%) poorly differentiated neuroendocrine carcinomas were studied. Overall, 76.31% of the tumors were positive for different types of sstrs with variable intensity of the membranous staining whereas 36.95% were positive for D2R alone. The sstr2A was the most frequently expressed, followed by sstr2B, sstr1, and sstr5. Co-expression of sstrs and D2R was seen in 88.23% of positive tumors. The high rates of sstr2A and sstr2B and in a lower extent of sstr5 expression are of great importance for more accurate imaging, staging and targeted therapy of the disease. The co-expression of sstrs and D2R in a significant number of the studied cases offers a potential therapeutic alternative for GEP-NETs.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / metabolism
  • Child
  • Digestive System Neoplasms / metabolism*
  • Digestive System Neoplasms / pathology
  • Digestive System Neoplasms / surgery
  • Female
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Neuroendocrine Tumors / metabolism*
  • Neuroendocrine Tumors / pathology
  • Neuroendocrine Tumors / surgery
  • Receptors, Dopamine / metabolism*
  • Receptors, Somatostatin / metabolism*
  • Young Adult

Substances

  • Biomarkers, Tumor
  • Receptors, Dopamine
  • Receptors, Somatostatin