BCR and acute lymphoblastic leukemia: The majority of precursor B-ALL are classified in the 5th edition of the World Health Organization Classification of Hematolymphoid Tumors (WHO-HAEM5) according to aneuploidy changes, which include high hyperdiploidy (over 50 chromosomes) and hypodiploidy (less than 44 chromosomes), well-known chromosomal rearrangements (KMT2A rearrangements, ETV6::RUNX1 fusion, TCF3::PBX1 fusion, BCR::ABL1 fusion, or IGH::IL3 fusion), or the newly identified other genetic drivers (BCR::ABL1-like ALL, intrachromosomal amplification of chromosome 21 (iAMP21), ETV6::RUNX1-like ALL, TCF3::HLF) [5,6].