Given the frequent occurrence of NRAS and KRAS mutations in myeloid malignancies with Mo7/del(7q), we generated cohorts of Mx1-Cre; KrasG12D/+ and Mx1-Cre; NrasG12D/+ mice either lacking or harboring the 5G2 deletion and induced Cre recombinase expression by injecting them with a single dose of polyI-polyC at weaning [8, 9]. This evidence concerns the gene MX1 and myeloid neoplasm.