ATRX and astrocytic tumor: In accord with previous reports, among the 41 tumor samples with IDH1-R132H positive, 34 lacked ATRX nuclear protein, while 53 samples of 74 astrocytic tumors with IDH1-R132H negative expressed ATRX, indicating a strong association between ATRX loss and IDH1-R132H (Figure 2A; p<0.0001, Chi-Square test).