PBX1 and infection: Our observation of gene enrichment pathways in ETV6-RUNX1 involving immunity and infection pathways (8/10 pathways with a significant association are related to immune function) is a potentially exciting avenue for future analysis, as it may relate to previous reports that have suggested abnormal immune response as a major factor shaping the trajectory of leukemogenesis.31,32 In the TCF3-PBX1 subtype, we identified a remarkable enrichment for genes in the neuroactive ligand-receptor interaction pathway.