Juvenile Myelomonocytic Leukemia and other myelodysplastic/myeloproliferative neoplasms

Abstract

Juvenile Myelomonocytic Leukemia (JMML) is a clonal hematopoietic disorder that usually occurs in early childhood, characterized by hyperactivation of the RAS signaling pathway. About 90% of patients have mutations in 1 of 5 genes (PTPN11, NRAS, KRAS, NF1, CBL) that define genetically and clinically distinct subtypes of the disease, with a highly variable clinical course. Allogeneic hematopoietic stem cell transplantation (HSCT) remains the therapy of choice for most patients with JMML, although children with CBL mutations and few of those with N-RAS mutations may have spontaneous resolution of hematologic abnormalities. The results of HSCT in patients with JMML have progressively improved over time, but relapse is still an important cause of treatment failure.