Since STAT3 plays one of the key roles in cancer development and progression and mediates the interaction of CLL and bone marrow cells which is crucial for maintaining viable CLL cell populations even after chemotherapy [24], the effect of Pt(S-pr-thiosal)2 on the level of phosphorylated STAT3 in BCL1 cells was analyzed by flow cytometry. The gene discussed is STAT3; the disease is B-cell chronic lymphocytic leukemia.