EGFR and glioblastoma: According to the EGFR status, gene copy number and type of amplification, tumors have been categorized into three groups [7]: GBM with high level of EGFR amplification as double minutes (dmin), in which the fraction of cells with amplification is higher than 20% and with more than 25 EGFR signals per cell, GBM with low level of EGFR amplification as insertions into different loci on chromosome 7, with a 5–20% of cells with amplification and less than 20 EGFR signals per cell, and GBM without EGFR amplification.