Prognostic Value of Somatostatin Receptor Subtypes in Pancreatic Neuroendocrine Tumors

Objectives Studies on the expression of somatostatin receptor (SSTR) subtypes in pancreatic neuroendocrine tumors (PNETs) are rare. The aim of this study was to determine the expression of the SSTR subtypes via immunohistochemistry analyses and assess the correlation between SSTR subtype expression and prognosis. Methods We examined 199 patients with PNET who underwent surgical resection between January 1995 and December 2010 at the Asan Medical Center. For all cases, medical records, including demographic data, clinical symptoms, radiological findings, postoperative treatment outcomes, and expression of SSTR subtypes, were carefully reviewed. Results In total, 162 (81.4%) PNETs expressed more than 1 SSTR subtype. Functioning PNET expressed significantly more SSTR subtypes, compared to nonfunctioning PNET. The SSTR2(+) and SSTR5(+) groups had better prognosis than the SSTR2(-) (P = 0.009) and SSTR5(-) groups (P = 0.03), respectively. In the grade 2 PNET of 2010 World Health Organization classification, the SSTR(+) group had better prognosis than SSTR(-) group. Conclusions The expression of SSTR 2 and 5 were related with good prognosis of PNET. In World Health Organization grade 2 PNET, the SSTR(+) group had better prognosis than SSTR(-) group. The SSTR expression(+) by immunohistochemistry might be related with good prognosis of the patients with surgically resected PNET.