JAK2 and acute myeloid leukemia: Group I harbored activating mutations in FLT3, MLL fusions and are classified as AML M5; Group II was enriched for loss of function TP53 mutations and three of the four cell lines were CML and thus had BCR-ABL1 fusions; Group III was characterized by activating mutations in genes involved in growth factor signaling such as RAS or JAK2, whereas no clear pattern was detected for Group IV.