These genes are either a component of the spliceosome, such as SF3B1, or auxiliary splicing factors, including U2AF1, SRSF2, ZRSR2, that assist the execution of the splicing process where mutations in these genes was shown to have prognostic impact in myeloid malignancies.15 In the 5th edition of the WHO Classification of Hematolymphoid tumors,16,17SF3B1 mutations have now replaced ring sideroblasts to become a subgroup in clinical diagnosis. This evidence concerns the gene U2AF1 and myeloid neoplasm.