As already known, all the mice inoculated with p185BCR/ABL-transduced cells rapidly developed a CML-like myeloproliferative disease defined by splenomegaly (400–1200 mg spleen weight) and high numbers of Mac1 (monocytes- macrophage) and Gr1 (granulocytes) and a low number of B220 (mature B-cell) expressing cells (Fig 6C and 6D). This evidence concerns the gene PTPRC and chronic myelogenous leukemia, BCR-ABL1 positive.