NRAS and myelodysplastic syndrome: To assess the prognostic significance of identified mutations, we focused on 22 genes with ≥ 5% mutation frequency (ASXL1, RUNX1, TET2, U2AF1, STAG2, DNMT3A, ETV6, SETBP1, EZH2, TP53, CEBPA, SRSF2, BCOR/BCORL1, KRAS/NRAS, GATA1/GATA2, NOTCH1/NOTCH2 and IDH1/IDH2) and considered factors including: age (< 60 yr vs. ≥ 60 yr), WHO classifications (progressive MDS vs. non-progressive MDS), treatment strategy (HSCT vs. non-HSCT) as well as IPSS-R and IPSS-R-M (molecular maker).