The Study On The Expression Of Mitotic Apparatus Proteins CENP-F And NuMA In Human Brain Gliomas

Objective: CENP-F and NuMA are two important mitotic apparatus proteins. They are reported to be related to malignant proliferation of most of human tumors abroad. But little was reported about the relation of malignant proliferation of gliomas to them abroad and home. We have previously reported that CENP-F is over expressed in human brain gliomas. The aim of this article is to detect the expression of CENP-F and NuMA in human brain gliomas at the levels of proteins and genes, and to investigate the relevance of overexpression of CENP-F and NuMA and malignant proliferation and prognosis of human brain gliomas.Methods: (1) Seventy formalin-fixed, paraffin-embedded gliomas (including 58 cases of astrocytomas) were obtained from the Pathology Department of the First Affiliated Hospital of Anhui Medical University during the year of 2001 and 2004. All samples were examined by two senior pathologists and were confirmed as gliomas. At the same time, the clinical pathologic data of all patients were collected from the Patient's Condition Department of the First Affiliated Hospital of Anhui Medical University. Twenty-four normal brain tissues (non-tumor brain tissues) were obtained as normal control from surgical resections of trauma patients, for whom a partial resection of normal brain tissue was required as decompression treatment for their severe head injuries to reduce increased intracranial pressure. The SP immunohistochemical staining method was used to detect the expression of PCNA, Ki-67, CENP-F and NuMA in 70 cases of human gliomas of various pathological types and grades and 24 cases of non-tumor brain tissue samples. (2) Ten fresh tumor tissues and five fresh normal brain tissues were collected from the First Affiliated Hospital of Anhui Medical University during the operation of neurosurgery. All tissues were diagnosised as gliomas or non-tumor tissues by two senior pathologists. The expression of CENP-F mRNA was examined by semi-quantity reverse transcription-polymerase chain reaction (RT-PCR) in 10 frozen specimens of human brain gliomas and 5 non-tumor brain tissues,β-actin was chosen as internal control.(3) Follow-up was performed on 40 cases of astrocytomas among 70 cases of gliomas.(4) Four fresh tumor tissues (including tumor tissues, corresponding tissues beside tumors and non-tumor tissues 2-5cm remote from the tumor) were collected from the First Affiliated Hospital of Anhui Medical University during the operation of neurosurgery. All tissues were diagnosised as gliomas or non-tumor tissues by two senior pathologists. The expression of NuMA was examined by western blotting assay in 4 cases of human brain gliomas.Results: (1) PCNA,Ki-67 and CENP-F proliferating libeling index (PLI) values in 70 cases of gliomas were 44.02%±29.37%,17.01%±17.68% and 36.80%±27.23% respectively; In non-tumor brain tissue samples, no expression of Ki-67 was detected, and PCNA and CENP-F PLI values were 12.11%±19.81% and 9.06%±8.27%; There were statistically significant between gliomas and non-tumor brain tissue samples(P<0.01).(2) The correlation between the increasing grade and various histological types and PCNA,Ki-67 and CENP-F PLI values were statistically significant. However, no correlation was detected between the age and sex of the patient and any one of three markers.(3) The expression of CENP-F mRNA was higher in 10 specimens of human gliomas than in 5 specimens of non-tumor brain tissues. Moreover, the expression of CENP-F mRNA between low-grade and high-grade gliomas showed significant difference (P<0.05). Bivariate correlation analysis showed statistical difference between CENP-F mRNA and the labeling indices of Ki-67 (Pearson correlation coefficient, r=0.801, P<0.05).(4) The expression of CENP-F and Ki-67 proteins were significantly different between low-grade and high-grade astrocytomas, the expression of high-grade astrocytomas is higher than that of low-grade ones (P<0.05). Forty patients with glioma were followed up, two cases were lost. With simple analysis and multivariate analysis, higher expression of CENP-F protein and tumor malignancy showed significant danger to survival.(5) The positive percentage of the expression of NuMA by immunohistochemistry in gradeⅠ+Ⅱ,ⅢandⅣgliomas were 42.4%, 74.1% and 70.0%, and 29.2% in normal brain tissues. There was a significant difference between brain gliomas and normal brain tissue (P < 0.01). The expression of NuMA was significantly correlated with histopathological grade (P<0.05),but it was not related with histopathological class of the tumors (P>0.05).(6) The level of NuMA in tumor tissues is higher than in corresponding tissues beside tumors. No expression of NuMA was detected in any tumor tissues.Conclusions: (1) The over-expression of CENP-F and NuMA was associated with the proliferating activity in human brain gliomas. CENP-F and NuMA genes may play an important role in the malignant progression in gliomas.(2) PCNA,Ki-67 and CENP-F, three tumor markers may be used to evaluate the tumor grade and to asses the malignancy in human gliomas.(3) The expression of CENP-F and Ki-67 proteins reflected the change of tumor cell proliferation activity, and was significantly correlated with astrocytoma malignancy. The expression of CENP-F, Ki-67 proteins and tumor malignancy may be prognostic parameters of astrocytomas.