About 75% of B-ALL patients exhibit abnormal chromosomal numbers or translocations (Mullighan 2012), which can generate fusion genes, including ETV6::RUNX1, TCF3::PBX1, BCR::ABL1, MLL-related fusion genes, etc. (Harrison and Foroni 2002; Onciu 2009). The gene discussed is KMT2A; the disease is acute lymphoblastic leukemia.