Notably, the expression of the genes for BLK, HCK and LYN in primary leukemic cells from KMT2A/MLL-R+ ALL patients was differentially and significantly amplified regardless of the age group compared to the expression levels in leukemic cells from B-ALL patients without KMT2A/MLL gene rearrangements. The gene discussed is BLK; the disease is acute lymphoblastic leukemia.