BCR and Splenomegaly: The clinical picture of JMML can be somewhat non-specific, and until very recently most children with JMML were diagnosed solely upon meeting a certain number of clinical features, such as splenomegaly (present in >90% of cases at diagnosis), a white blood cell count >10,000/μL with circulating immature myeloid forms, an absolute monocyte count (AMC) >1000/μL, increased fetal hemoglobin for age, <20% blasts, and absent BCR/ABL fusion gene (Table 1) (5).