Interestingly, LIN28B overexpression is observed in specific subtypes of pediatric leukemia26, including juvenile myelomonocytic leukemias of fetal origin (JMML), characterized by high fetal hemoglobin levels and considered to arise from a stem-progenitor cell27, possibly of fetal origin24,28,29. This evidence concerns the gene LIN28B and juvenile myelomonocytic leukemia.