ACTIVATED STAT RELATED TRANSCRIPTION FACTORS IN ACUTE-LEUKEMIA

Cell proliferation and differentiation are under the control of cytoki nes and growth factors. Different signaling pathways are involved in t he transmission of a specific signal through successive phosphorylatio n and dephosphorylation of proteins leading to gene transcription nece ssary for growth and differentiation. The cytokines and growth factors activate the Stat family of transcription factors. The Jak-Stat pathw ay is essential for cytokine signal transduction. Dysregulation of thi s cascade might lead to uncontrolled hematopoiesis. Studies have been carried out to examine the functionality of this pathway in cells from patients with acute leukemia. Members of the Stat protein family (Sta t1, Stat3 and Stat5) are constitutively activated in cells collected f rom some acute leukemias suggesting dysregulation of the Jak-Stat path way. Evidence of the existence of constitutively activated spliced var iants of Stat3 and StatS proteins are described. The mechanisms of suc h activation remain to be clarified.