Angiogenesis in multiple myeloma.

Angiogenesis is the process of new blood vessel formation, and normally occurs during embryonal growth, wound healing, and the menstrual cycle. It is essential for the proliferation and metastases of most malignant neoplasms. There is now growing evidence that angiogenesis is increased and is likely important in multiple myeloma. Recent evidence suggests that angiogenesis is greater in multiple myeloma compared to monoclonal gammopathy of undetermined significance (MGUS). Angiogenic cytokines such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are expressed by neoplastic plasma cells, and may play a role in the increased angiogenesis seen in myeloma. In a study of 400 patients with plasma cell disorders, microvascular density (MVD) was significantly higher in smoldering myeloma, newly diagnosed myeloma, and relapsed myeloma compared to controls, MGUS, and primary amyloidosis. In another study involving 74 newly diagnosed patients with myeloma treated at the Mayo Clinic, overall survival was significantly longer in patients with low-grade angiogenesis compared to those with high-grade or intermediate-grade angiogenesis. The finding of increased angiogenesis in myeloma provides the rationale for the study of antiangiogenic therapy in this disease.