Effect of over-expression and knockdown of TIMP-1 on tumor growth in vivo. (A) Bars represent liver weights of BALB/c mice challenged with splenic injections of wild type and modified CT26 cells as indicated. The whole experiment was terminated, when the first animal had to be euthanized due to ethical guidelines. +: mean. (B) Photograph of resected livers. Any increase in liver weight is due to an increase in tumor burden. (C) Percentage of tumor tissue (area) as compared to pre-existent liver parenchyma.