AFF1 and acute lymphoblastic leukemia: In China, the statistical results of Sun et al [19] on 57 cases of 11q/23 MLL-r pediatric patients with ALL showed that the MLL-AF4 accounted for 29.8% and MLL-PTD accounted for 26.3%, followed by MLL-AF9 (22.8%), MLL-ENL (12.3%) and MLL-AF10 (8.8%), respectively.