ATRX and astrocytic tumor: We classified astrocytic tumors into IDH1-R132H positive and IDH1- R132H negative tumors and then defined IDH1-R132H positive and ATRX loss tumors as A1, IDH1-R132H negative tumors with high Ki-67 expression as A3, and grouped IDH1-R132H positive with ATRX expression and IDH1-R132H negative tumors with low Ki-67 expression into A2.