EGFR and central nervous system cancer: To find the genes most specifically associated with oligodendrogliomas with 1p19q codeletion, we selected the probe sets that were consistently (> 2-fold) and significantly (t test p < 0.001) overexpressed in these gliomas when they were independently compared to each of the 4 other samples groups (i.e., gliomas with EGFR amplification, cortex samples, corpus callosum samples and glioblastoma cancer stem cells).