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.