It is well-known that leukemic cells in chronic lymphocytic leukemia (CLL) successfully resist apoptosis in vivo, but they are prone to apoptosis in vitro. Recent research shows that this fact can be explained by interactions of malignant cells with T-cells, stromal cells, nurse-like cells, endothelial cells and dendritic cells in microenvironment of bone marrow, lymph nodes and spleen where the CLL are protected from apoptosis and stimulated to increased proliferation.
Angiogenesis participates in progression of CLL by enhanced supply of nutrition as well as protection from apoptosis. This new knowledge on CLL biology will translate in future into novel therapeutic approaches: clinical studies are already testing new agents able to disrupt the communication of leukemic cells with microenvironment as well as angiogenic processes.