OLIG2 and neoplasm: •BRAFV600E expression induces aggressive gliomas in mice when combined with Ink4a/Arfloss or activation of the Akt pathway•Tumors with BRAFV600E and Ink4a/Arf deletion do NOTexpress GFAP, S100 and Olig2, but strongly express Nestinshow evidence of diffuse infiltration, aberrant vasculature and necrosis•No evidence of tumor formation in mice injected with BRAFV600E alone