Of note, two of the BCP‐ALL PDXs harbor structural variants in TCF3::HLF (ALL‐7) or NUP214::ABL1 (ALL‐19), which are associated with a higher risk of poor outcome (Supporting Information S1: Table S1), while ALL‐2 was derived from a patient who underwent multiple relapses and died from their disease.23, 24. The gene discussed is TCF3; the disease is acute lymphoblastic leukemia.