Molecular characterization of glioblastomas. a, Western blot analysis to show MAP2, Nestin and GFAP expression in cultured GBM1, GBM2, GBM3, GBM4 (lanes 1–4) cells and control brain lane 6; lane 5, negative control blood cells. b, Multiplex analysis allowing to detect EGFR amplification. Lanes 1, 2, 3 samples showing amplification of EGFR; lane 4, negative control; lane 5, positive control. c, Sequencing of P53 normal sample and sample presenting mutation of P53 (GBM6). d, LOH analysis. Lane a, blood sample; lane b, tumor sample frozen tissue contaminated with cells presenting ROH (ROH, retention of heterozygosity); lane c, lack of cells with ROH, DNA isolated from aggregate.