MMP9 and breast cancer: This pathway is controversial as Zhang et al. have found that nanomolar concentrations of BPA increased wound closure and invasion of BC cell lines MDA-MB-231 and BT-549 through increased expression matrix metalloproteinases 2 (MMP2) and MMP9 protein and mRNA levels, although it displayed no effect on the expression of vimentin and fibronectin in triple negative breast cancer (TNBC) cells.