The genes were classified into three clusters: one cluster of genes overexpressed in gliomas with EGFR amplification (gene cluster A, 698 genes), one cluster of genes overexpressed in oligodendrogliomas with 1p19q codeletion (gene cluster C, 488 genes) and a smaller cluster of genes expressed by some samples of both groups (gene cluster B, 180 genes). The gene discussed is EGFR; the disease is central nervous system cancer.