It is important to note that MMP-9 and plasmin are also capable of processing TGFβ latency complexes thus potentially explaining why residual levels of active TGFβ were identified in the conditioned media derived from MMP-2 null osteoblasts (Fig. 6D) and also why TGFβ neutralizing antibody treatment with MMP-2 null conditioned media could further reduce the number of tumor colonies (Fig. 7B). Here, PLG is linked to neoplasm.