To examine the effects of MMP derived fibroblasts in vivo, FaDu tumor cells were injected alone or in combination with WT, MMP-2 null, MMP-9 null, or MT1-MMP null fibroblasts into the oral cavity of SCID mice in ratios of 1:2 and 1:3 (tumor cell:fibroblast). Here, MMP9 is linked to neoplasm.