Although it cannot be absolutely excluded that PBSA‐mediated inhibition of cell invasion is partly mediated by regulation of other MMPs or TIMPs not investigated in this study, these findings suggest that PBSA‐mediated down‐regulation of MMP expression and proteolytic activity, in particular MMP‐2 and MMP‐9, might inhibit the invasive potential of ovarian cancer cells in response to mitogenic stimulation. The gene discussed is MMP9; the disease is ovarian cancer.