SOAT1 and essential thrombocythemia: Myeloproliferative neoplasms (MPNs)—the main subtypes of which are polycythemia vera (PV), essential thrombocythemia (ET) and myelofibrosis (MF)—are a group of haematological malignancies characterised by the constitutive activation of the Janus kinase (JAK) / signal transducer and transcription activator protein (STAT) pathway in clonal myeloid precursors.