Major (MDS-related) criteria include i) dysplasia of at least 10% of cells in one or more major BM lineage(s) (erythroid, neutrophilic, megakaryocytic) or an increase in ring sideroblasts (RS) of ≥ 15% (or ≥ 5% in the presence of a SF3B1 mutation), ii) an increase in myeloblasts of 5-19% in dysplastic BM smears (in the absence of AML-specific gene rearrangements) or 2-19% myeloblasts in peripheral blood smears, and iii) a MDS-related (5q-, -7, complex, etc.)karyotype (Table 1). Here, SF3B1 is linked to myelodysplastic syndrome.