ABL1 and acute lymphoblastic leukemia: When comparing patients with BCR::ABL1 positive and BCR::ABL1 negative B-precursor ALL for several disease characteristics, including age, sex, ECOG, CCI, blood levels at diagnosis, karyotype, extramedullary manifestations, CNS infiltration, risk factors, and the rate of therapy-related ALL, we observed significantly higher leukocyte counts at diagnosis in the subgroup of BCR::ABL1 positive patients (p = 0.005) (Table 1).