Expression of hypoxia-inducible factor-1α and its role in glioma

Objective To investigate the expression of hypoxia inducible factor-1α (HIF-1α) and its significance in glioma. Methods A total of 60 glioma specimens including 11 cases of grade Ⅰ (8 pilocytic astrocytoma, 2 choroids plexus papillomas, 1 myxo-papillary ependymoma), 20 cases of grade Ⅱ (11 diffuse astrocytoma, 5 oligodendroglioma, 2 ependymoma, 2 pleomorphic xanthoastrocytoma), 21 cases of grade Ⅲ (12 anaplastic astrocytoma, 6 anaplastic oligodendroglioma, 3 anaplastic ependymoma) and 8 cases of grade Ⅳ (glioblastoma), were enrolled in the study. Immunohistochemical assay was carried out to detect the expression levels of HIF-1α, and the results were analyzed statistically in correlation with the volumes of glioma as well as the age and sex of patients. Results 1) There was positive HIF-1α expression in the glioma specimens, mostly observed in the cytoplasm and/or nucleus with obvious heterogeneity. Siginifcantly enhanced expression could be found in the margin of infiltration areas of the tumor. The negative expression was found in the negatively-controlled specimens and other 10 specimens of normal brain tissue. The positive HIF-1α expression rate for the glioma specimens was 71.67% (43/60), among them, 27.27% (3/11) for grade Ⅰ, 70.00% (14/20) for grade Ⅱ, 85.71 (18/21) for grade Ⅲ and 100% (8/8) for grade Ⅳ, respectively. The positive expression rate of HIF in higher pathological grade glioma was obviously higher than that in lower pathological grade glioma. And the differences were statistically significant (χ2 = 15.907, P 0.01). The expression intensity was positively correlated with the pathological grade (rs = 0.480, P 0.01) of glioma. 2) The HIF-1α expression was not correlated with the age and sex of the patients and the volum of tumors (P 0.05). Conclusion The HIF-1α expression is correlated with the pathological grade of glioma.