As we were unable to detect binding of any of the BSPs to proMMP-2, there is evidently a need to re-assess the potential ability of BSP to bind to and activate proMMP-2 in the context of cancer cell metastasis although we cannot rule out the possibility that much more highly glycosylated BSP than the bovine BSP we used here could conceivably mediate an interaction with proMMP2. Here, IBSP is linked to cancer.