Distribution of epidermal growth factor receptor protein correlates with gain in chromosome 7 revealed by comparative genomic hybridization after microdissection in glioblastoma multiforme

In a recent study, 23 microdissected areas of 10 glioblastoma multiforme (G BM) were investigated for quantitative genomic aberrations using comparativ e genomic hybridization (CGH). To validate the chromosomal aberrations, as revealed by CGH after microdissection, parallel tissue sections were staine d immunohistochemically with an antibody that detects both wild-type epider mal growth factor receptor (EGFR) and the deletion mutant form of the recep tor (EGFRvIII). Immunostaining was correlated with CCH data of chromosome 7 , because chromosome 7 is the most frequently aberrant chromosome in GEM th ere four of 10 tumors), and this aberration often indicates an abnormality of EGFR. Nine of nine areas that showed gain in or amplification (2 areas) of chromosome 7 with CGH contained EGFR-immunoreactive cells. Only three of 14 areas without abnormality of chromosome 7 in CGH contained EGFR-irnmuno reactive cells; eleven of 14 areas were immunonegative. Our findings demons trate a strong correlation between immunohistochemistry of EGFR and the cop y numbers of chromosome 7, as revealed by CGH after microdissection in glio blastoma multiforme.