The inhibition of skin and ovarian cancer metastasis formation in gelatinase B/MMP-9 knockout mice can be reversed by transplantation of normal bone marrow cells, implicating inflammatory cell gelatinase B/MMP-9 in the metastatic process and adding to the role of gelatinase B/MMP-9 in primary tumour initiation, promotion and expansion [170,390]. Here, MMP9 is linked to neoplasm.