PTPN11 and juvenile myelomonocytic leukemia: In 2003, missense mutations in PTPN11 were discovered as somatic events occurring in juvenile myelomonocytic leukemia (JMML), as well as in childhood myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) [15], marking a milestone in the development of the understanding of the underlying mechanisms of these hematological malignancies.