The term “Philadelphia–like” or “BCR/ABL1–like” ALL was defined in 2009 by Boer et al. In their study, they described a subset of ALL with negative (BCR/ABL1, histone-lysine methyltransferase 2 [KMT2A], and transcription factor 3 [TCF3], and pre-B-cell-leukemia transcription factor 1 [PBX1]) but had behavior like “true BCR/ABL1–positive cases” [6]. Here, PBX1 is linked to acute lymphoblastic leukemia.