Thus, the Type 2 pattern exhibits a two-phase tumor evolution—an “early” phase with normal Pten/chr19 and relative stable near-2N genomes in the SVZ and a “late” phase with Pten/chr19 loss and highly unstable sub-4N genomes in the spatially segregated distant brain parenchyma, while the Type 1 pattern only has a one “late” phase during tumor evolution (Fig. 3i). The gene discussed is PTEN; the disease is neoplasm.