Abstract: Objective: To investigate the relationship between the expression level of early growth response gene- 1 (egr- 1) in human glioma, and the tumor grade, cell proliferation and apoptosis of the tumors. Methods: Seventy- three human glioma specimens with different grades of malignancy were studied using in situ hybridization, in situ cell death detection (TUNEL method) and immunohisto-chemistry. Results: All of the 73 gliomas expressed egr- 1 mRNA and EGR- 1 protein (100%). Not only was the positive cell density of egr- 1 mRNA and EGR- 1 protein increased with the degree of tumor malignancy but also their expression differences were significant among groups of grade- Ⅰ to Ⅱ, Ⅲ and Ⅳ (P<0.01). Both the expression of proliferating cell nuclear antigen (PCNA) and tumor- cell apoptosis were detected in all of the 73 glioma cases (100%). The PCNA- positive tumor cells were increased but apoptotic tumor cells decreased with an enhancement of the tumor malignancy. There were significant differences among the glioma cases of various malignant grades (P<0.05~0.01). The positive cell density of egr- 1 mRNA expression, EGR- 1 protein and PCNA protein were positively correlated with one another (r=0.685~0.999, P<0.01). However, each one of them was negatively correlated with the number of apoptotic tumor cells (r=- 0.758~ - 0.775, P<0.01). Conclusion: These results suggest that the expression level of egr- 1 mRNA has potential value in the evaluation of biological behavior of gliomas. Overexpression of the egr- 1 gene in glioma cells could possibly promote cell proliferation, inhibit apoptosis and play an important role in the development and malignant progression of glioma.