Hypoxia in the tumor microenvironment triggers a variety of genetic and adoptive responses that regulate tumor growth. Tumor hypoxia is often associated with a malignant phenotype, resistance to therapy, and poor survival. The objectives of this study were to evaluate the expressions of carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) in astrocytic gliomas and to relate patterns of expression with prognosis, that is with histological grade and survival. We investigated 78 World Health Organization (WHO) grade II, III, and IV astrocytic gliomas. CA9 expression was examined in paraffin-embedded sections by immunohistochemistry. Fourteen tumors were grade II, 30 were grade III, and 34 were grade IV. It was found that CA9 expression was significantly associated with a higher-grade histology (p<0.001). There were 3 CA9 positive tumors in grade II (21.4%), 10 in grade III (33.3%), and 27 in grade IV (79.4%). For all tumors and WHO grade II, overall survival was found to be significantly dependent on CA9 expression (p=0.004, p=0.01). Furthermore, VEGF expression was found to be significantly related to tumor grade (p=0.02) and tended to be related to overall survival (p=0.1). However, no relation was found between the expression of CA9 and VEGF (p=0.17). Nevertheless, the expressions of CA9 and VEGF were found to be associated with tumor grade and possibly with survival. Further studies on a larger patient population are needed to determine the correlation between the expressions of CA9, and VEGF in astrocytic gliomas and clinical outcome.

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