Stromal fibroblasts secrete multiple matrix metalloproteinases (MMP)1 that can promote tumor cell growth, survival, invasion, angiogenesis, and metastasis. Basigin on the surface of carcinoma cells, stimulates production of MMP-1 (interstitial collagenase), MMP-2 (gelatinase A), and MMP-3 (stromelysin). Basigin has been shown to co-immunoprecipitate with caveolin-1. The second Ig domain of Basigin is required for this association, which leads to decreased Besigin self-association on the cell surface. Therefore, caveolin-1 is a negative regulator of CD147 self-association, and its MMP-inducing activity.