Surviving SCH66336-treated mice showed no signs of leukemia/lymphoma at the end of the treatment period.

After 220 days of treatment with SCH66336, one mouse (A39) was killed. (A) Sagittal section of the sternum. Note the normal maturation in the myeloid and the lymphoid lineage, a slight increase in the presence of mature granulocytes and the lack of signs of leukemic cells. (B) Transverse section of the spleen. Note the normal architecture of red and white pulp. Original magnification: panel A ×40; panel B, ×20. (C, D) FACS analysis of bone marrow cells. Bone marrow cells were isolated and stained with fluorescence-labeled antibodies against B-cell (CD45R), T-cell (Thy1.2), and myeloid (GR1, Mac1) markers. We detected a slight increase in myeloid cells, but no increase in B-lineage cells, which could indicate developing B-cell leukemia.