AFF1 and acute lymphoblastic leukemia: We observed increased levels of H3K79me2 in infant-ALL- and FL-specific genes such as IGF2BP1 (Fig. 5d) and HOXB4 (Fig. 5e) in CRISPRMLL-AF4+ ALL, further suggesting that MLL-AF4 actively maintains the expression of these fetal-specific genes in MLL-AF4 infant-ALL.