Tumor suppressor PTEN, oncogene Ki-67 and hypoxia-inducible factor 1α (HIF-1α) played important roles in the malignant progression of multiple human tumors. In this study, the expression and the clin. significances of PTEN, Ki-67 and HIF-1α in human gliomas were mainly investigated to lay a foundation for the assessment of prognosis, the mol. pathol. diagnosis and the treatment of gene targeting in glioma patients. Expression status of PTEN, Ki-67 and HIF-1α was detected by immunohistochem. in 83 cases of human glioma specimens. Correlations of the expression between each other, as well as correlations between the expression and malignant grade were also analyzed. All the normal brain tissues showed PTEN pos. and Ki-67 neg. expression, while 10% (1/10) specimens showed HIF-1α pos. In gliomas, PTEN expression was significantly decreased (P = 0.001), while expressions of Ki-67 (P < 0.001) and HIF-1α (p = 0.001) were both increased. With the ascending of the malignant grade, PTEN expression was significantly decreased (P < 0.001) but expressions of Ki-67 and HIF-1α were increased (P < 0.001, for both). Furthermore, relevant analyses indicated that correlation between PTEN expression and Ki-67 or HIF-1α expression was neg. (r = -0.289 and -0.304, resp.; P = 0.008 and 0.005, resp.), while correlation between Ki-67 expression and HIF-1α expression was pos. (r = 0.833; P < 0.001). Expression of tumor suppressor PTEN was down-regulated, while expression of oncogene Ki-67 and HIF-1α was up-regulated in gliomas. Down-regulation or inactivation of PTEN tumor suppressor, up-regulation of oncogene Ki-67 and HIF-1α might play important roles in the malignant progression of gliomas. Combined detection of PTEN, Ki-67 and HIF-1α proteins might play important clin. roles in the assessment of the malignancy and prognosis of gliomas.