Human colon carcinoma (HCT-116) growth response to different mAb treatments in nude mice. (Top) Each mouse was treated systemically with 320 μg mIgG (○) and 320 μg mAb C11C1 (•). Data are mean ± SEM. The treatment was administered intraperitoneally every 2 days for 16 days. The C11C1 mice showed a tumor growth plateau from days 13 to 16, whereas the group receiving mIgG continued to grow. The difference in volume was statistically significant at all points mIgG versus C11C1 (P < .003). (Bottom) Note that the C11C1-treated group had smaller, paler tumors, whereas the mIgG group had larger tumors and hemorrhagic foci. Nine of 10 mice had tumors at the time of autopsy (day 16) versus 10 of 10 in the mIgG group. The decrease in weight in the C11C1 group was statistically significant (P = .0012). The ruler in the picture measures inches.