S100A4 and osteosarcoma: The findings reported here are, therefore, in accordance with those of the Lewis lung carcinoma cell line model described above, where MMP9 was produced in all of the cell lines, independently of the level of S100A4 (Takenaga et al, 1994), but contrast with studies in an osteosarcoma cell system which implicated S100A4 in the control of both the levels of MMPs and of the tissue inhibitors of matrix metalloproteinases (TIMPs) (Bjornland et al, 1999).