科研之友
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摘要
background: astrocytomas represent the most frequent primary tumors of the central nervous system. admittedly, part of tumor growth is due to inhibition of programmed cell death: the apoptosis. this phenomenon is basically regulated by the balance between anti-apoptotic (e.g.: b-cell lymphoma protein 2 [bcl-2]) and pro-apoptotic (e.g.: bcl-2 associated protein x [bax]) molecules. objective: the present study aimed to evaluate the expression of bcl-2 and bax in human astrocytic tumors of different histopathological grades. material and method: an immunohistochemical study of those proteins using the avidin-biotin-peroxidase method was performed in 55 astrocytomas (13 grade i, 14 grade ii, seven grade iii and 21 grade iv) and five samples of non-tumor brain tissue (control group). results: the bcl-2 and bax positive indices tended to increase according to astrocytomas graduation, with general positivity of 43.26% and 24.67%, respectively. these proteins were not detected among non-tumor specimens. bcl-2 labeling scores demonstrated a tendency to increase in accordance with histopathological advancing, while bax values were similar in all graduations. the combined analyses of these proteins expression presents a significant correlation with tumor grade (p %26lt; 0.05; h test), witch is more evident among glioblastomas (grade iv) in comparison with low-grade astrocytomas (i and ii) (p %26lt; 0.05; u test). bcl-2/bax ratio denoted increasing of cellular survival orientation of the astrocytic tumors according to malignant progression. conclusions: the results indicate alterations in bcl-2 and bax proteins expression as resultant of the tumorigenic process in astrocytomas, with increasing predominance of the anti-apoptotic profile in consonance of malignant transformation. in this way, we propose that bcl-2 overexpression in astrocytic tumors may be indicative of more aggressive phenotypes, furthermore configuring a potential therapeutic target.
