The results indicate that MGMT is constitutively and extremely expressed in astrocytic cells, which in part sup ports the frequent failure of alkylating based mostly therapy in astrocytomas. On the other hand, GST? and TdS expression appears to outcome in the neo plastic procedure, that’s in accordance using the habitual resistance of astrocytic tumors to cytotoxic medicines detoxified by glutathione and also to folate pathway inhibitors, respectively. In contrast, large levels of TopoIIA in diffuse astrocytomas may well constitute a favorable predicament for chemotherapeutic drugs that stabilize the cleavable complicated formed involving TopoII and DNA. The conflicting final results in grade IV tumors reinforce their heterogeneity. Ultimately, we suggest that this protocol could possibly be of predic tive value in picking out appropriate medication for chemotherapy and avoiding medication expected to be ineffective on account of enhanced expression of distinct resistance aspects.
PA 11. c MYC EXPRESSION Is definitely an Different PATHWAY Leading TO p53 MUTATION AND EGFR OVEREXPRESSION IN ASTROCYTOMA TUMORIGENESIS, AN IMMUNOHISTOCHEMICAL Research Bronner P. A. Gon?alves, Germano P. V. Lima, M rio H. G. Faria, and Silvia H. B. Rabenhorst, Division of Pathology and Forensic Medicine, XL184 ic50 Federal University of Cear, Fortaleza Cear Brazil Molecular scientific studies of astrocytic tumors have delineated particular genetic alterations which are distinguished while in the neoplastic context. p53 mutations and EGFR overexpression are hallmarks of astrocytoma tumorigenesis, defining mutually unique pathways. How ever, there may be a subset of tumors that cannot be effectively explained by these alterations. In selleck the last decade, the c MYC oncogene has become identified as being a centerpiece within the tumorigenic procedure of various human cancers.
Latest proof reinforces the direct and indirect participation with the c MYC professional tein in regulating the cell cycle, differentiation, apoptosis, genomic instabil ity, and angiogenesis, while the pathways usually are not entirely understood. c MYC expression is described in glial neoplasms and correlated with tumor progression, but its impact on astrocytoma tumorigenesis remains unclear. The aim in the current examine was to assess the contribution of c MYC expression in astrocytic tumors in comparison with p53 mutation and EGFR overexpression. Immunohistochemical analysis in the p53/p21WAF1/ CIP1, EGFR, and c MYC proteins utilizing the avidin biotin peroxidase procedure was carried out in fifty five astrocytomas and 5 samples of non tumor brain tissue. p53 constructive indices and labeling indices showed a tendency to boost in accordance to malignant progression, while p21 PIs and LIs demonstrated the opposite inclination, except for large scores in grade IV tumors. The p53/p21 profile unveiled a tendency to larger incidence of p53 mutations in agreement with gradation, despite the lower value for grade IV.