الفهرس 
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Abstract
INTRODUCTION: The proliferation index (PI) is a measure of the proportion of cells in a tumor that have the capacity to divide and proliferate at a given point in time. Methods used to determine the proliferation index include Ki-67 antigen expression and flow cytometry. Most malignant gliomas are characterized by high PCNA and Ki-67 labeling indices and by high frequency of aneuploidy, Angiogenesis is considered together with proliferative activity to be important indicators of tumor behavior. Correlation was found between tumor vascular density and tumor cell proliferation. In spite of the fact that the degree of aneuploidy increases with malignancy in the CNS tumors, aneuploidy is also found in many benign tumors.The independent variation of the proliferative activity, ploidy and histopathological features suggests that the use of multiple analysis may allow more accurate prediction of gliomas patient survival AIM OF THE WORK: Evaluation of the applicability of the qualitative histopathologic data in grading of glial tumors , correlation between proliferation potential detected by proliferation markers and the different grades diagnosed by routine H&E staining methods, assessment of the vascular status of various gliomas grouped in this study and evaluation of its relation to the grade and proliferation potential and evaluation of the role of flow cytometry in separating gliomas according to their DNA ploidy into diploid and aneuploid groups and to what extent this is correlated to the different grades and proliferation potential in the same tumor group. MATERIAL AND METHODS: This study was performed on 60 cases of glial tumors collected as resected specimens at the pathology department, Mansoura Faculty of Medicine during the period from March /2001 to June /2003. The following procedures were done: A) Histopathological and immunohistochemical study: (1-Hematoxylin and Eosin, 2-Immunohistochemistry using Ki-67 monoclonal antibody to assess the proliferative activity and F VIII monoclonal antibody to assess the MVD (microvessel density) of the studied tumors. B) Flow cytometry: done for all cases for assessment of DNA ploidy state and S-phase. RESULTS: Grading of gliomas is a very important for assessment of the prognosis and this could be helped by other factors in addition to histopathological criteria. Mitosis, necrosis and vascular proliferation are important histopathological criteria in assessment of the grade of glial tumors. However these findings can be seen exceptionally in some low grade gliomas. Although mitosis can be seen in low grade glial tumors, it is very important to remember that it is usually scarce and occasional. The presence of frequent mitotic activity should be taken as a strong indicator for malignancy and higher grade in any glial neoplasm CONCLUSION: Measurement of the proliferation potential by Ki-67 and by estimation of S-phase is very accurate parameter in assessment of the grade of gliomas On the other hand measurement of MVD is not a helpful method in assessment of the grade of glial tumors, however, DNA ploidy could be a helpful method in differentiation between low and high grade gliomas.