BACKGROUND:: Both proliferating cell nuclear antigen and P27 protein are important factors to regulate cell cycle. While, the combination of them can provide exactly objective markers to evaluate prognosis of patients with brain glioma needs to be further studied based on pathological level. OBJECTIVE:: To observe the expressions of proliferating cell nuclear antigen and P27 protein in both injured and normal brain glioma tissues and analyze the effect of them on onset and development of brain glioma. DESIGN:: Case contrast observation. SETTING:: Department of Neurosurgery, the Second Affiliated Hospital of Xiʼan Jiaotong University. PARTICIPANTS:: A total of 63 patients with brain glioma were selected from Department of Neurosurgery, the Second Affiliated Hospital of Xiʼan Jiaotong University from July 1996 to June 2000. There were 38 males and 25 females and their ages ranged from 23 to 71 years. Based on pathological classification and grading standards of brain glioma, patients were divided into grade I – II (n =30) and grade III – IV (n = 33). All cases received one operation but no radiotherapy and chemiotherapy before operation. Sample tissues were collected from tumor parenchyma. Non-neoplastic brain tissues were collected from another 12 non-tumor subjects who received craniocerebral trauma infra-decompression and regarded as the control group. There were 10 males and 2 females and their ages ranged from 16 to 54 years. The experiment had got confirmed consent from local ethic committee and the collection was provided confirmed consent from patients and their relatives. All samples were restained with HE staining so as to diagnose as the brain glioma. While, all patients with brain glioma received radiotherapy after operation and their survival periods were followed up. METHODS:: Primary lesion wax of brain glioma was cut into serial sections and stained with S-P immunohistochemical staining. Brown substance which was observed in tumor nucleus was regarded as the positive expressions of both proliferating cell nuclear antigen and P27 protein. Automatic imaging analytic system was used to quantitatively analyze staining results of tumor. MAIN OUTCOME MEASURES:: To compare the expressions of proliferating cell nuclear antigen and P27 protein in brain glioma tissues and non-tumor brain tissues and investigate the effect of various sexes, ages, survival periods and severities on the expressions of them in brain tissues. RESULTS:: There was no significant difference of sexes and ages in the expressions of proliferating cell nuclear antigen and P27 protein (P > 0.05); however, the expressions of proliferating cell nuclear antigen and P27 protein were milder in non-tumor brain tissues than those in the brain glioma tissues (P < 0.05). Expression of proliferating cell nuclear antigen in brain tissue of grade III – IV severity was stronger than that of grade I – II severity, and the expression in ≥ 5-year survival periods were also stronger than that in < 5-year survival periods (P < 0.05). In addition, expression of P27 protein in brain tissue of grade III – IV severity was stronger than that of grade I – II severity, and the expression in ≥ 5-year survival periods were also stronger than that in < 5-year survival periods (P < 0.05). CONCLUSION:: Abnormal expressions of proliferating cell nuclear antigen and P27 protein in human brain glioma are closely related to onset, development and prognosis of tumor.