The fourth paper by X. Liu et al. “Molecular targets for the treatment of juvenile myelomonocytic leukemia” describes the outstanding progress made in identifying the mutations associated with activation of the Ras pathway in juvenile myelomonocytic leukemia (JMML), several of which are already targets of drugs that are being tested such as Ras and SHP-2. The gene discussed is PTPN11; the disease is juvenile myelomonocytic leukemia.