Since both DDR1 overexpression and MT1-MMP depletion were able individually to increase apoptosis in MDA-MB-231 cells, we hypothesized that the double transfection of DDR1 and shMT1-MMP in these cells could synergize to decrease cell growth and increase collagen-induced apoptosis to a level similar to that observed in luminal-like breast carcinoma cells. Here, DDR1 is linked to breast carcinoma.