The Dominant Somatostatin Receptor in Neuroendocrine Tumors of North Indian Population

ABSTRACT Introduction Neuroendocrine tumors (NET) express different types of somatostatin receptors (SSTRs) that bind to synthetic analogs with variable affinity. It is important to know the expression profile of SSTRs to predict biological effect of somatostatin analogues. We studied SSTR2 and SSTR5 expression by immunohistochemistry (IHC) to assess the dominant subtype in NETs and correlate the expression with histological prognostic parameters. Materials and methods Fifty-three consecutive cases of NET from all sites were evaluated for SSTR2 and SSTR5 expression by IHC. The expression was correlated with histological features of NETs. Results Forty-four cases were resected specimens and 9 were small biopsies. Nine of 53 cases (16.9%) were functional tumors. There were 24 NETs from gastrointestinal tract (GIT), 19 from pancreas and 10 from miscellaneous sites. Overall SSTR expression was seen in 43 NETs (79.2%). Somatostatin receptor 2 was expressed in 30 cases (56.6%) and SSTR5 in 39 cases (73.6%). Somatostatin receptor 2 expression showed near significant negative correlation with tumor grade and lymph node metastasis (p = 0.05). Somatostatin receptor 5 expression showed significant negative correlation with lymph node metastasis (p = 0.008) and tumor size (p = 0.02). Anatomic location and tumor necrosis were not significantly different. Somatostatin receptor 5 was dominant subtype expressed in all NETs with intense expression. Conclusion Somatostatin receptor 5 expression was the dominant subtype and expressed in small sized tumors. Somatostatin receptor 2 was expressed more in low grade NETs. Somatostatin analogs can be effective both in functional and nonfunctional NETs and can be useful in both resectable and nonresectable or metastatic tumors. How to cite this article Krishnani N, Kumari N, Singh RK, Shukla P. The Dominant Somatostatin Receptor in Neuroendocrine Tumors of North Indian Population. World J Endoc Surg 2015;7(3):60-64.