MMP1 and neoplasm: Besides, CAFs remodel the ECM by secreting multiple matrix proteins (e.g., fibronectin and collagen I) and producing MMPs (e.g., MMP-1, MMP-3), facilitating the degradation of normal ECM structure along with increasing matrix stiffness, so as to boost tumor cell proliferation, angiogenesis, and immune suppression (17, 73).