MX1 and myeloproliferative neoplasm: Distinct Ras mutations exhibit variable behavior, for instance, the induction of heterozygous KrasG12D/+ expression in the hematopoietic system alone through Mx1-Cre leads to a rapid and highly penetrant myeloproliferative disease (MPD) modeling human MDS/MPN, but does not lead to AML progression [25].