MMP9 and neoplasm: In human neuroblastoma, gelatinase B/MMP-9 recruits bone marrow-derived leukocytes and support cells to tumour vessels, regulating vessel maturation [264] and the VEGF/gelatinase B/MMP-9 axis has been implicated in the robust angiogenic response associated with TrkAIII oncogene promotion of neuroblastoma tumorigenicity [265].