MMP9 and breast cancer: The role of this integrin in promoting cell invasion and motility by up-regulating MMP2 and MMP9 as well as cytoskeletal organization in a PI3K-dependent manner has been reported for a variety of cancers5,15,27,38.Therefore, in this study, we also examined the expression levels of various integrin subunits, which are known to bind to TSP-1, both at a protein and transcription levels in wild-type and TSP-1-null mammary tumor cells.