Inhibition of VEGF signaling pathways in multiple myeloma and other malignancies.

Due to its direct effects on endothelial cells, circulatory endothelial progenitor cells, hematopoietic stem cells, immune cells, osteoclasts, osteoblasts and neurons, vascular endothelial growth factor (VEGF) is linked to tumor cell development, progression, metastatic osteolysis and drug resistance, as well as clinical features such as metastatic osteolysis. Importantly, recent advances in the understanding of mechanisms of action of antiangiogenic drugs/VEGF-inhibitors have fundamentally changed treatment regimens in cancer. VEGF plays a key role not only in solid tumors but also in hematologic malignancies, including multiple myeloma (MM). Despite recent advances in our understanding of MM pathogenesis and novel therapies (bortezomib and lenalidomide), it remains incurable. Our own and others' work suggest that VEGF-inhibitors e.g., the small molecule VEGF receptor inhibitor pazopanib, may also improve patient outcome in MM.