Human neuroblastoma tumors xenotransplanted in MMP-9 (+/+) and MMP-9 (−/−) mice showed that bone marrow-derived MMP-9 regulates the recruitment of leukocytes and endothelial cells along with pericytes from bone marrow into tumor stoma leading to neovascularization and tumor progression [35]. The gene discussed is MMP9; the disease is neoplasm.