ABL1 and acute lymphoblastic leukemia: BCR::ABL1 status, ALL phenotype (T- or B-ALL), the intensity of conventional treatment applied (protocol originally intended for patients ≤ 55 years vs. >55 years), cytotoxic treatment for a previous malignancy or CCI (0 vs. 1 vs. 2–5) had no significant impact on OS and EFS.