Expression of insulin-likegrowthfactor-1 by canineinsulinomas and their metastases

Abstract

Abstract The long-term prognosis after surgical resection of canineinsulinoma is poor. Signs of hypoglycaemia often recur soon after surgery because tumour tissue has only been resected partially and/or functional (micro-)metastases were present. Using quantitative real-time PCR, the expression of 16 target genes was compared between primary canineinsulinomas and their corresponding metastases. There was significantly higher expression of genes encoding for growth hormone (GH) and insulin-likegrowthfactor-1 (IGF-1) in metastases compared to their primary tumours. Immunohistochemical examination of proteins of the GH–IGF-1 axis revealed expression of GH, IGF-1 and GH receptor (GHR) in both primary insulinomas and metastases. Immunohistochemical staining for IGF-1 was significantly higher in metastases compared to primary tumours. Keywords Canine; Insulinoma; β-cell tumour; Growth hormone; Insulin-likegrowthfactor