BCL2 and leukemia: STAT3 is broadly hyperactivated in hematologic malignancies, head and neck cancers, leukemia and a subset of solid tumors and oncogenesis and promotes oncogenesis by up-regulating the expression of target proteins associated with cell proliferation, differentiation, apoptosis (Bcl-2, Bcl-xL), angiogenesis, metastasis and immunity [3–7].