iPSC lines were first differentiated to forebrain-patterned SOX2+/NESTIN+/SOX10− neural progenitor cells (NPCs) and then to GFAP+ astrocytes, the cell-of-origin of astrocytoma, using a modified astrocyte differentiation protocol27,28 (Fig. 1a and Supplementary Fig. 1b). This evidence concerns the gene GFAP and astrocytoma (excluding glioblastoma).