Immunohistochemical expression of somatostatin receptor subtypes 2 and 5 in colorectal cancer

Abstract

BACKGROUND: To determine the immunohistochemical expression levels of the somatostatin receptor subtypes 2 and 5 (Sst2 and Sst5) in patients with colorectal cancer (CRC) and to investigate the association of Sst2 and Sst5 expression with clinicopathological parameters. MATERIALS AND METHODS: A retrospective analysis of formalin-fixed and paraffin-embedded CRC surgical specimens from 81 patients assessed by immunohistochemistry for Sst2 and Sst5 expression. RESULTS: Sst2 and Sst5 expression levels showed significant, negative association with CRC invasion and liver metastasis (P values < 0·05) while Sst2 also showed significantly increased expression in lower-grade tumours as well as in tumours located in the rectum (P values < 0·05). Patients with CRC expressing either Sst2 or Sst5 had significantly longer survival rates (P values < 0·05), although Sst expression was not found to be an independent predictor of survival after controlling for other known prognostic clinicopathological variables (P values > 0·05). CONCLUSIONS: The present data confirm the relationship of Sst2 and Sst5 expression levels with reduced tumour aggressiveness.