Expression of the Hypoxia Marker Carbonic Anhydrase 9 Is Associated with Anaplastic Phenotypes in Meningiomas

• Main Authors: Yoo, Heon, Baia, Gilson S, Smith, Justin S, McDermott, Michael W, Bollen, Andrew W, Vandenberg, Scott R, Lamborn, Kathleen R, Lal, Anita
• Format: Conference Proceeding
• Language: English
• ISSN: 1531-5010; 1532-0065
• DOI: 10.1055/s-2007-981753

The purpose of this study was to evaluate the prevalence of hypoxia in meningiomas using endogenous hypoxia marker carbonic anhydrase 9 (CA9) and to relate the expression of CA9 to tumor vascularity, histopathological grade, and clinical parameters such as recurrent tumor status and patient survival. Expression of CA9 and CD34, an endothelial cell marker, were examined in serial paraffin-embedded sections by immunohistochemistry in 25 grade I, 17 grade II, and 20 grade III meningiomas. Areas of immunoreactivity were semiquantitatively scored and correlated to clinical variables using SAS statistical software. Approximately 50% (29/62) of all meningiomas contained regions of hypoxia as judged by expression of CA9, and this expression was significantly associated with higher grade histology (p = 0.001). In contrast, vascularity, as assessed by the percent of vascular hotspots, was inversely associated with tumor grade (p = 0.023) and was not associated with CA9 expression. Among lower-grade meningiomas, CA9 expression tended to be more common in recurrent tumors. Hypoxia in meningiomas is associated with aggressive phenotype. Further studies to define the contribution of hypoxia to meningioma pathophysiology are warranted.