| Autor: |
Faria, Mário H. G., Gonçalves, Bronner P. A., do Patrocínio, Régia M. do S. V., de Moraes-Filho, Manoel O., Rabenhorst, Silvia H. B. |
| Předmět: |
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| Zdroj: |
Neuropathology; Dec2006, Vol. 26 Issue 6, p519-527, 9p, 2 Charts, 1 Graph |
| Abstrakt: |
Astrocytomas represent the most frequent primary tumors of the central nervous system. Recently, the determination of the proliferative index of astrocytic tumors by different methods has been proposed as a valuable tool for tumor grading and also as a prognostic marker. The aim of the present study was to evaluate the expression of cell proliferation-related proteins in human astrocytic tumors of different histopathological grades (WHO). An immunohistochemical study of the Ki-67, Topoisomerase IIα (Topo IIα) and c-MYC proteins using the avidin-biotin-peroxidase method was performed in 55 astrocytomas (13 grade I, 14 grade II, 7 grade III and 21 grade IV) and five samples of non-tumor brain tissue (control group). Ki-67, Topo IIα and c-MYC positive indices tended to increase according to malignant progression, were absent in non-tumor brain tissue and showed maximum values in high-grade astrocytomas (III and IV). A gradual increase in Ki-67 antigen expression was observed in agreement with mitotic index and histopathological classification. The same was not observed for Topo IIα and c-MYC. Ki-67 antigen detection in more than 8.0% of the tumor cells distinguished astrocytoma grade IV, while a labeling index between 1.5 and 8.0% characterized astrocytomas grade III and values below 1.5% discriminated low-grade tumors (I and II). These results indicate that Topo IIα and c-MYC expression is associated with cell proliferation in astrocytomas, although not in an exclusive way. Moreover, Ki-67 antigen was found to be the best marker of cellular proliferation, and its expression predicts the grade of astrocytic tumors. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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