In addition, most of the cases (up to 80%) of infant ALL and a few cases (5%) of childhood ALL are associated with the rearrangements of the KMT2A (Lysine Methyltransferase 2A) gene that encodes for a histone methyltransferase, which confers a poor prognosis [100,101,102,103]. This evidence concerns the gene KMT2A and acute lymphoblastic leukemia.