ABL1 and acute leukemia: Mixed-phenotype acute leukemia (MPAL) is a rare subgroup of acute leukemia, accounts for < 0.5% of all cases of acute leukemia.[1] According to the 2022 WHO classification, MPAL is divided into 5 subtypes: MPAL with BCR::ABL1 rearrangement, MPAL with rearranged KMT2A, MPAL with B-cell/myeloid features not otherwise specified, MPAL with T-cell/myeloid features not otherwise specified, and acute undifferentiated leukemia.