FURIN and neoplasm: To further obtain a conclusive notion on differential growth kinetics of tumor xenografts with altered p21 genetic background, HCT116 p21−/− (left) and parental p21+/+ (right) cells were implanted subcutaneously to both flanks of each nude mouse which allows better tumor monitoring because of their lack of fur coat and the tumors were allowed to grow for a more extended period.