Mutations involving the cohesin complex can be seen in myeloid neoplasms, with individual mutational frequencies of ~12% AML, ~8% MDS, ~6% chronic myeloid leukemia, ~1% MPN and ~10% in CMML.69 These mutations frequently coexist with other myeloid relevant mutations, including TET2, ASXL1 and EZH2. 69 The prognostic impact of these mutations remains to be determined. The gene discussed is TET2; the disease is chronic myelomonocytic leukemia.