Abstract: Objective: To investigate the expression and significance of the CDC2 and Cyclin B1 genes in the tumorigenesis and malignant progression of gliomas using tissue microarrays. Methods: A tissue microarray containing 118 specimens was constructed, including all pathological grades of human brain glioma tissues, cellular spheroids of human brain glioma cell lines and their implanted xenografts,brain tumor stem cells, neural stem cells and relevant specimens as controls. Results: The expression of CDC2 and Cyclin B1 was located in cell nuclei. The positive expression rates of CDC2 and Cyclin B1 in 71 cases of human brain glioma tissues were 54.9% and 52.1%, respectively. However, the positive expression rates of CDC2 and Cyclin B1 in 11 normal adult brain tissues were 18.2% and 9.0%, respectively, and there was a significant difference between the diseased cases and the controls (P<0.05).The co- expression rate of CDC2 and Cyclin B1 was 89.7%. The expression of CDC2 and Cyclin B1 was positively correlated (r=0.90, P<0.01). The differences in expression of both proteins between all grades were also significant (P<0.05). Furthermore, the pathological grades were positively correlated with the positive expression rates of CDC2 and Cyclin B1 (r=0.982, P=0.018; r=0.959, P=0.041). High expression levels were observed in the glioma cellular spheroids cultured in vitro, subcutaneous implanted xenografts of nude mice, human fetal brain tissues and bone marrow of nude mice, but not in the spheroids of brain tumor stem cells and neural stem cells. Conclusions: Co- expression of CDC2 and Cyclin B1 increased with the malignant progression of brain gliomas, demonstrating that these gene products function to promote malignant progression in glioma. As well, their lower expression in neural stem cells and brain tumor stem cells and elevated expression in SHG44 glioma cells and GBM revealed that CDC2 and Cyclin B1 play roles in inhibiting differentiation of tumor cells. Further study of the molecular etiology of glioma is crucial.