MMP2 and breast cancer: Interestingly, a main component of caveolae, caveolin-1, has been reported to promote MMP14-dependent pro-MMP2 activation in Ewing sarcoma cells contributing to their metastatic potential, however, in epithelial breast cancer cells, but not in mesenchymal melanoma cells, caveolin-1 leads to a reduced cell migration due to the decreased secretion of MMP2 and MMP9 [136,137,138].