Angiogenesis and Antiangiogenesis in Multiple Myeloma

Multiple myeloma progression is characterized by a dense interaction between cancer cells and bone marrow microenvironment. The interactions of myeloma cells with various stromal cells and extracellular matrix components are the main regulator of the biological processes that underlie the progression of the disease and of the classic symptomatology correlated. The bone marrow of myeloma patients has recognized autocrine and paracrine loops that regulate multiple signaling pathways and the malignant phenotype of plasma cells. One of the pivotal biological processes which are responsible for myeloma progression is the formation of new vessels from existing ones, known as angiogenesis. It represents a constant hallmark of disease progression and a characteristic feature of the active phase of the disease. Near angiogenesis, other two ancestral processes were active in the bone marrow: vasculogenesis and vasculogenic mimicry. These processes are mediated by the angiogenic cytokines, interleukins, and inflammatory cytokines directly secreted by plasma cells and stromal cells. Neovascularization is also mediated by direct interaction between plasma cells and the various components of bone marrow microenvironment. The observation of the increased bone marrow angiogenesis in multiple myeloma and its correlation with disease activity and overall survival led to consider angiogenesis as a new target in the treatment of multiple myeloma.