Astrocytic neoplasms comprises around 60% of the Central Nervous System tumors, affecting mainly adults in a highly productive phase of life, and showing poor prognosis despite of the available treatments. A better knowledge of the molecular biology of this group of tumors is necessary to understand their evolution and to plan the treatment in a better way, as well as to develop new therapies. Hence, this study had the aim the analysis of modifications of gene TP53 related to changes in the number of copies and the presence of polimorphisms in exons 4 to 11, considered hotspots for mutations. A total of 14 samples of different malignant grades were analyzed by interphasic FISH using locus-specific probes for gene TP53 and centromeric for chromosome 17, and by SSCP for screening polymorphism in exons 4 to 11. The results were compared between tumors with grades I and II (benign) to those with grades III and IV (malign). The results concerning the locus specific probes (gene TP53 and centromere of chromosome 17) showed that the occurrence of deletions and amplifications were statistically important when compared to nuclei with normal copy number. However, these alterations were not related to the age, sex or malignancy. On the other hand, these alterations were found more frequently in patients with tumors with intermediate grades (III). SSCP experiments revealed polymorphisms in exons 5, 7 and 10, and although they were not realted to the malignancy of tumors, the samples with polymorphism corresponded to the patients with shorter survival after treatment, suggesting a relation between the mutations in these exons and higher aggressively tumors.
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