KMT2A and acute lymphoblastic leukemia: It has been suggested that alterations in MLL-r play an important role in the activation of oncogenes, while the role of partner genes fused to them is unclear, while some studies revealed that ALL with MLL-r positive were similar in most morphological and histochemical features, and childhood ALL with MLL-r positive, regardless of the type of partner gene, had an extremely poor prognosis [24].