In other words, our model predicts that the incidence of MPNST, and breast cancer46–50 as well as juvenile myelomonocytic leukemia (JMML)51–53 that are associated with NF1, would be much higher in NF1 patients if it were not due to the repressive role of the NF1+/− microenvironment. This evidence concerns the gene NF1 and juvenile myelomonocytic leukemia.