MMP8 and cancer: Secondly, in clonal cell lines derived from MDA-MB-435 cancer cells that display high (M-4A4) or low (NM-2C5) metastatic ability, overexpression of MMP-8 reduced the metastatic ability of M-4A4 cells, whereas ribozyme-mediated gene knockdown of MMP-8 enhanced metastasis of the NM-2C5 line (7, 13).