Overexpression of Mutant p53 in Human Anaplastic Astrocytoma and Glioblastoma Multiforme

ABSTRACT

A total of 30 cases of cerebral gliomas, including 6 cases of low grade astrocytomas, 6 anaplasticastrocytoomas and l8 glioblastomas multiforme, was examined immunohistochemically to demonstrate the overexpression of mutant forms of p53 protein and to evaluate their relationships with histological subtypes. A p53 monoclonal antibody was applied to the routine formalin fixed, paraffin-embedded tissues for this study using microwave-assisted avidin-biotin method. Overexpression of p53 protein was identified in 4 out of 6 anaplastic astrocytomas (66.7%) and in l3 out of l8 glioblastomas multiforme (72.2%). No immunohistochemical positivity of p53 was found in adjacent normal brain tissue, gliosis and 6 cases of astrocytoma. These results suggest that overexpression of mutant p53 may be an important step in the development and progression of malignant astrocytoma, especially of the aggressive subtypes of glioma, including glioblastoma multiforme.