NRAS and myelodysplastic syndrome: Shiozawa and coworkers have purified CD34+ cells from MDS patients and have analyzed their transcriptome; according to the gene expression patterns, MDSs can be subdivided into two groups: an immature progenitor subtype, associated with a high risk of transformation to AML and with TP53, RUNX1 and NRAS mutations; an erythroid megakaryocyte subtype, associated with a low risk of AML transformation [29].