Selective amplification of the cytoplasmic domain of the epidermal growth factor receptor gene in glioblastoma multiforme.

Primary brain tumors of glial origin often overexpress epidermal growth factor receptors (EGF-Rs). This may be associated with amplification of the EGF-R gene. We have examined tissue from 23 glioblastoma multiforme tumors and found amplification and rearrangement of the EGF-R gene in four of these. The cytoplasmic domain of the EGF-R gene was invariably amplified in these four tumors, while the epidermal growth factor binding domain was not uniformly amplified in three of these tumors. Western blot analysis of the EGF-R protein revealed high levels of a truncated EGF-R protein in two of the four tumors with EGF-R gene amplification.