SF3B1 and acute myeloid leukemia: While some mutations such as SF3B1 may cause a slowly progressive MDS, others, including Rat sarcoma virus (RAS)-pathway mutations, are associated with increased blast counts and, therefore, higher risk of progression to Acute Myeloid Leukemia (AML), which occurs when myeloblasts account for greater than 20% of nucleated cells in the bone marrow [14,15].