U2AF1 and myelodysplastic syndrome: Since most, if not all, studies on U2AF1 pathogenic mutations do not differentiate the two U2AF1 isoforms nor profile their expressions, they are not comprehensive in understanding the pathogenic mechanisms of MDS by not recognizing the potential functional impacts of the dynamic expressions of U2AF1 isoforms on the phenotypes that are attributed to U2AF1 mutations (26–28,34–36,50).