EGFR gene amplification ‐ rearrangement in human glioblastomas

Abstract

Immunostaining using an affinity‐purified rabbit polyclonal antibody against the extracellular domain of the epidermal‐growth‐factor receptor (EGFR) showed over‐expression occurring in a fraction of tumor cells in 17 out of 18 human glioblastomas and in a majority of cells in 7 of the 18. Southern‐blotting technique using a full‐length EGFR cDNA probe showed a variable degree of amplification in 10 of the 17 glioblastomas, which was associated with EGFR over‐expression in each case. In 2 of the glioblastomas with EGFR gene amplification, a rearrangement of the gene affecting the extracellular domain of the receptor was identified and DNA sequence analyses revealed an identical deletion‐rearrangement of 801 base pairs between exons 2 to 7, resulting in an in‐frame fusion of exons I and 8.