TGF-β Activity and Expression of its Receptors in B-Cell Chronic Lymphocytic Leukemia

Abstract

B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in Western countries and results from the accumulation of B-lymphocytes which are functionally abnormal and predominantly non-cycling in vivo. Consequently, it is important to understand why B-CLL cells accumulate in G0 phase. Since TGF-β is an important negative regulator of the immune system, a loss of responsiveness to this factor might provide a selective advantage to B-CLL cells. Here we review data on the role of TGF-β in B-CLL. We show that the B-CLL cell response to TGF-β signals is abnormal in vitro (inhibition of proliferation and induction of apoptosis). This lack of response of B-CLL cells to TGF-β inhibition appears to be accompanied by a decrease or a loss of TGF-β receptor expression.

Key Words:

• TGF-β
• receptors
• apoptosis
• proliferation
• B-CLL