Multilineage involvement of haematopoiesis by this KIT mutation, particularly in a multi-mutated context, also involving other genes (e.g., SRSF2, ASXL1, DNMT3A, RUNX1, EZH2, CBL and NRAS) found to be frequently mutated in other myeloid neoplasms, have recently emerged as a genetic background associated with malignant transformation of SM. The gene discussed is EZH2; the disease is systemic mastocytosis.