Study Of Relationship Between E2F-1 And Rb's Expressions And Malignancy In A Human Glioma

PurposeIt has been confirmed by recent studies that the development of glioma is an effect of multi-gene mutation and an evolvement of series of multi-steps,relation to activation of many oncogenes and inactivation of tumor suppressor genes.Recently,people find there is some obvious abnormality of the expression of suppressor gene Rb in glioma. Transcription factor E2F-1 whose overexpression will result in cell proliferation and tumor formation,which is not only involved in the regulation of cell circle,but also interact with Rb.Now,there is not any report about the study of the relationship of Rb and E2F-1 in our country.The purpose of this experiment is that studying the expression of Rb and E2F-1 in different grades about human glioma and evaluating relations between Rb,E2F-1 and pathological grades of tumor.Method1.Specimen45 cases human brain glioma specimen which were cut off by surgery in neurosurgery department China Medical University affiliated NO.1 hospital from July 2006 to March 2007.Male 27 cases and female 17 cases ages are from 26 to 78 years old.All the cases didn't accept radio- or chemical-therapy before surgery.Specimens are fixed by 10%neutral formalin,routine paraffin imbedding,4μm serial section,and HE staining confirmed diagnosis.GradeⅠ12 cases,gradeⅡ15 cases,GradeⅢ10 cases,gradeⅣ8 cases. 2.Main agentRb,E2F-1 anti-human monoclonal antibody of mouse,SABC staining kit and DAB kit both bought from Wuhan Boster Biological Technology,LTD.3.Empirical method and result assessmentUsing SABC immunohistochemical method to detect the expression information of Rb and E2F-1 in human brain glioma.Immunohistochemical positive is defined as brown drops or uniform brown exist in nucleus or cytoplasm.Count the positive cells percent in each cut sheet,no positive cells marked with(-),positive cells less than 10%(+),positive cells 10%～50%(+ +),positive cells more than 50%(+ + +).4.Statistical analysis:Use SPSS13.0 software for statistical management.Enumeration data is analyzed through X~2 test.There is statistical significance(P＜0.05).ResultE2F-1 positive staining mainly locates in nucleus and cytoplasm,brown fine grain like,sporadic weak-positive expresses in well differentiated group(gradeⅠ～Ⅱ), expression rate is 48.1%(13/27).However,expression is obviously enhanced in poorly differentiated group(gradeⅢ～Ⅳ),expression rate is 83.3%(15/18).There is significant deviation between tow groups(P＜0.05).Rb positive staining mainly locates in cytoplasm.In well differentiated group(gradeⅠ～Ⅱ),there are 20 positive expression cases in 27 cases(74.1%);and in poorly differentiated group(gradeⅢ～Ⅳ), there are 5 positive expression cases in 18 cases(27.8%).There is also significant deviation between tow groups(P＜0.05).DiscussionGlioma is the most frequent intracranial malignant tumor.The development of glioma has intimate correlation with activation of many oncogenes and inactivation of tumor suppressor genes.Rb is a very important suppressor gene,whose over-phosphorylation and promoter's methylation is the primary reason of the loss of Rb gene's function.This reseach shows that there are expressions of Rb protein in gliomas,and there is significant deviation between two groups(P＜0.05).High grade group has higher absence rate,which suggests that Rb genetic mutation or absence plays an important role in occurrence and development of glioma,and is closely related to malignant differential degree.E2F-1 plays a key role in regulating cell cycle progression and cellular proliferation.The higher expression of E2F-1 in glioma is considered another important factor of generation and development of glioma.This experiment also shows that the expression of E2F-1 is more in poorly differentiated group than in well differentiated group.Otherwise,high grade group has higher E2F-1 expression rate,and higher Rb absence rate,suggests that Rb may inhibit some component of E2F-1 participating cell transcription.ConclusionResult of this research demonstrate that expression of Rb and E2F-1 has connection with glioma grades,suggest that two different kinds of genes have regulation,induction or information transferring effect.Detecting expression of Rb and E2F-1 is a significant biological parameter to make criteria for glioma malignant grades. And it provides a new way to study pathogenesy,prognosis prediction and treatment from different genetic changes.