Juvenile Myelomonocytic Leukemia (JMML) is a myeloproliferative neoplasm that affects mainly infants and young children, driven by Ras pathway mutations, hyperactivation of Ras/Mitogen-activated protein kinase pathway and PI3K/mTOR signaling leading to excessive formation of leukemic cells in the myelomonocytic and red cell lineage. Here, MTOR is linked to juvenile myelomonocytic leukemia.