EP13.01 ARE GLUCAGON RECEPTORS FOUND IN HUMAN MENINGIOMAS?

Abstract BACKGROUND Glucagon receptors are mostly expressed in adipocytes and hepatocytes. Both somatostatin receptors (SSTRs) and glucagon receptors are G-protein coupled receptors, that are essential for regulation of metabolism. SSTRs are used within theranostics and as a marker of meningioma in routine diagnostic pathology with high sensitivity. Although the expression of SSTRs in human meningioma is extensively studied, there are no studies on the immunoreactivity of glucagon receptors. The aim of our study was to explore if glucagon receptors are expressed in human meningiomas, with similar diagnostic sensitivity as SSTRs. Hence, we investigated the immunohistochemical expression of glucagon receptors in a large series of human meningiomas and related the findings to WHO grade. MATERIAL AND METHODS Our study included 162 patients operated for a primary, intracranial meningioma (WHO 2016 grade 1 or grade 2) in the period of 1991 to 2000 at St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway. Three tissue microarrays (TMAs) from each tumor specimen underwent standardized immunohistochemical procedures. Sections were incubated overnight at 4°C with a polyclonal glucagon receptor antibody (Invitrogen, PA5-33595, dilution 1: 100). Immunoreactivity was evaluated by two consultant pathologists using staining index (SI). Tumors with SI > 3 were considered positive. RESULTS Glucagon receptors were detected in 79% of the tumors specimens, demonstrating a moderate sensitivity for human meningiomas. WHO grade 2 meningiomas had a significantly higher expression of glucagon receptors (p < 0.05). CONCLUSION Glucagon receptors are expressed in most human meningiomas, but to a less extent than SSTRs. The presence of glucagon receptors does not seem to hold potential as a diagnostic marker in meningiomas.