P19.04.B CHROMOGRANIN A IN HUMAN MENINGIOMAS

Abstract BACKGROUND Meningiomas are the most common intracranial tumor. The neoplasms are usually benign and slow-growing, but the recurrence rates are substantial. There is currently no established pharmaceutical treatment for patients suffering from meningioma, marking the need for a further understanding of tumor biology and investigation of treatment options. Somatostatin receptors are well-known to be present in human meningiomas and somatostatin analogs are investigated as a potential targeted treatment. The presence of somatostatin receptors may suggest a possible expression of other neuroendocrine proteins in human meningiomas. The neuroendocrine glycoprotein chromogranin A is a precursor for several biologically active peptides and contributes to the intracellular formation of secretory granules. Chromogranin A is a well-established neuroendocrine differentiation marker. To our knowledge the immunohistochemical expression of chromogranin A in human meningiomas is not previously investigated. The aim of this study was to investigate neuroendocrine differentiation in human meningiomas by using chromogranin A as an immunohistochemical marker. MATERIAL AND METHODS The immunohistochemical expression of chromogranin A were measured in tissue specimens from 162 patients operated for primary World Health Organization 2016 classification grade 1 or 2 meningioma in the period of 1991 to 2000 at St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway. Sections were incubated for 40 minutes in room temperature with a monoclonal chromogranin A antibody (clone DAK-A3, dilution 1:100). RESULTS None of the 162 tissue specimens of meningioma were immunoreactive for chromogranin A. CONCLUSION Chromogranin A was not immunohistochemically expressed in our series of 162 meningioma specimens, thus not supporting neuroendocrine differentiation in human meningiomas. However, as other neuroendocrine peptides (such as somatostatin receptors) are previously detected in meningiomas, further investigations are needed to conclude on the matter of neuroendocrine differentiation in meningiomas.