Immunophenotyping suggested that the leukemia in Osx-Cre+ p53fl/+ pRbfl/+ mice was similar to the previously reported EWS-FLI-induced erythroid/myeloid leukemia, in which EWS-FLI1 expression was driven by Mx1-Cre [29]. Here, MX1 is linked to myeloid leukemia.