ABL1 and mixed phenotype acute leukemia: As two separate entities of MPAL, BCR::ABL1 fusion gene induced by t(9;22)(q34.1;q11.2), also known as Philadelphia chromosome-positive (Ph+), was observed in 15%-30% of patients, especially in adults (8); whereas KMT2A rearrangement due to t(v;11q23.3) occurred more frequently in the pediatric cohort (16, 17).