Despite numerous clinical trials over the past 2 decades, the overall survival for children diagnosed with
diffuse intrinsic pontine glioma (
DIPG) remains 9-10 months.
Radiation therapy is the only treatment with proven effect and novel
therapies are needed.
Epidermal growth factor receptor variant III (
EGFRvIII) is the most common variant of the
epidermal growth factor receptor and is expressed in many
tumor types but is rarely found in normal tissue. A
peptide vaccine targeting
EGFRvIII is currently undergoing investigation in phase 3 clinical trials for the treatment of newly diagnosed
glioblastoma (GBM), the
tumor in which this variant receptor was first discovered. In this study, we evaluated
EGFRvIII expression in pediatric
DIPG samples using immunohistochemistry with a double affinity purified antibody raised against the
EGFRvIII peptide. Staining of pediatric
DIPG histological samples revealed expression in 4 of 9 cases and the pattern of staining was consistent with what has been seen in
EGFRvIII transfected cells as well as GBMs from adult trials. In addition, analysis of
tumor samples collected immediately post mortem and of
DIPG cells in culture by RT-PCR, western blot analysis, and flow cytometry confirmed
EGFRvIII expression. We were therefore able to detect
EGFRvIII expression in 6 of 11
DIPG cases. These data suggest that
EGFRvIII warrants investigation as a target for these deadly pediatric
tumors.