Are p53 mutations and p53 overexpression prognostic factors for astrocytic tumors?

Abstract

The p53 tumor supressor gene is the most frequently mutated gene in human cancers. Approximately 40% of astrocytic tumors have alterations of the p53 gene, which are considered to play an important role in tumorigenicity and malignant progression. Since the main functions of normal p53 are cell-cycle regulation and induction of apoptosis, p53 mutations are considered to be associated with rapid tumor growth and resistance to radiation and chemotherapy. Although in certain cancers, p53 mutations are considered a poor prognostic factor, the predictive role in astrocytic tumors is not clear. Immunohistochemical studies have shown conflicting results, probably because this technique fails to provide a reliable p53 gene status. Mutation analyses have shown the association between p53 mutations and shorter survival of high-grade gliomas only in pediatric patients, but not in adults. This may suggest that p53 mutations have a relatively lower impact on the survival of malignant astrocytomas than other gene alterations, which pediatric tumors rarely harbor.