Conversely, AML with biallelic TP53 inactivation carries a dismal prognosis and patients progressing from MPN should be included in clinical trials of experimental therapies to facilitate allogeneic stem cell transplantation; other patients with older age and/or co-morbidities deserve careful counselling regarding whether to proceed with intensive therapy at all. This evidence concerns the gene TP53 and myeloproliferative neoplasm.