Considering the critical interface between tumor cells and stromal cells in the search for targets for anticancer therapy.

In this issue of Cancer Cell, a paper by Lynch et al. demonstrates how the careful study of changes that occur at the interface between tumor cells and stromal cells led to the discovery of a new function for matrix metalloproteinase-7 (MMP-7) in the formation of osteolytic lesions in prostate cancer. The data suggest that MMP-7 inhibition could be a therapeutic target in prostate cancer.