RUNX1 and leukemia: It was first identified as a fusion partner of PDGFRβ in leukemia [9] and subsequently in a variety of fusions with AML1 [10,11], ABL [12], MN1 [13], JAK2 [14,15], EVI1 [16], CDX2 [17], and BTL [18] in hematopoietic malignancies.