It has previously been reported that cell proliferation in a 3D native (non-pepsin-extracted) type l collagen matrix required active MT1-MMP (in the case of cells engineered to overexpress the protease) and Tks5 (in the case of the endogenous protein in breast cancer cells) [21, 37]. The gene discussed is SH3PXD2A; the disease is breast carcinoma.