Angiopoietin-2 expression in B-cell chronic lymphocytic leukemia: association with clinical outcome and immunoglobulin heavy-chain mutational status

Chronic lymphocytic leukemia (CLL) has been considered for several years a disease of accumulation of relentless mature-looking malignant monoclonal B cells due to a presumeddefect in programmed cell death. However, several observations suggest that CLL cells are not immortal and that they require signals from microenvironment to maintain viability. Increased microvessel density in marrow and lymph node and increased levels of certain proangiogenetic factors in blood and urine of CLL patients were observed.2 Angiopoietin-2 (Ang-2) has a pivotal role in the disruption of stability and quiescence of mature vasculature that coincides with the reinitiation of vascular remodelling and angiogenic sprouting in adult, as occurs in tumors.