Thus, MDS/MPN-U cases could be further categorized into five molecular subtypes: ‘CMML-like’ (presence of biallelic TET2, TET2/SRSF2 or RUNX1/SRSF2); ‘aCML-like’ (presence of any of these gene mutation combinations: ASXL1/SETBP1, SETBP1/SRSF2, ASXL1/EZH2, RUNX1/EZH2); ‘MDS/MPN-RS-T–like’ (SF3B1 mutation, either alone or in combination with DNMT3A or JAK2; or DNMT3A/JAK2); ‘TP53’ (presence of TP53 mutations) and ‘Other’ (Figure 4). Here, JAK2 is linked to myelodysplastic syndrome.