We performed morphology, immunohistochemistry and STED confocal microscopy to investigate the expression and the subcellular localization of hnRNPK, NSUN1 and BRD4 in the pre-treatment clinical bone marrow specimens from normal controls and from the patients with cytogenetically normal MDS, specifically, refractory anaemia with multilineage dysplasia (RCMD) subtype, and AML. The gene discussed is HNRNPK; the disease is myelodysplastic syndrome.