BCR and acute leukemia: The 2016 WHO classification of myeloid and lymphoid neoplasms recognizes seven entities under the category of acute leukemias of ambiguous lineage (ALAL), including mixed phenotype acute leukemia (MPAL) with t(9;22)(q34.1;q11.2) BCR-ABL1, MPAL with t(v;11q23.3) KMT2A rearranged, MPAL B/myeloid NOS, MPAL T/myeloid NOS, MPAL not otherwise specified (NOS) rare types, acute undifferentiated leukemia (AUL), and acute leukemia of ambiguous lineage, not otherwise specified (ALAL NOS).