PBX1 and acute lymphoblastic leukemia: Included in this category was the BCR-ABL1 in-frame fusion gene that was supported by >180 spanning pair-end reads in both ALL 542 libraries, two in-frame fusions TCF3-PBX1 (135 and 145 spanning reads) and TPM4-KLF2 (12 spanning reads in each replicate) that were detected in both ALL 668 libraries, and KMT2A − MLLT4 (16 and 36 spanning reads) that was discovered in both AML 1867 libraries (Fig. 5).