EPIDERMAL GROWTH-FACTOR RECEPTOR AND P53 PROTEIN EXPRESSION IN HUMAN GLIOBLASTOMAS

p53 mutations and amplification of epidermal growth factor receptor (EGFR) gene are the most frequently detected genetic alterations in glioblastomas; thus, these changes seem to delineate two subgroups of glioblastomas: those originated de novo and those originated from preexistent low grade astrocytomas. Paraffin-embedded surgical specimens of 30 human glioblastomas were analyzed immunohistochemically for the presence of p53 protein and EGFR. Approximately half of the cases were p53 protein-positive while one-third were EGFR positive. Only three cases were positive for both p53 protein and EGFR. There was no difference between the average ages of patients with only-p53-positive, and double-negative tumors, while three glioblastomas with both p53 protein and EGFR immunopositivity occured in older patients (mean age 67.0 years, p < 0.02). Patients with only-EGFR-positive tumors were younger, but not significantly (44.3 years, p < 0.1). This study supports the notion that there are two main subpopulations of glioblastoma - with EGFR and with p53 protein overexpression.