Fig. 4.

5-FU–induced antiangiogenic maintenance in colorectal tumors. (A) Treatment schedule. (B) Growth rates of continuous NIIgG-treated, continuous VEGF blockade-treated, VEGF blockade and cessation-treated, and VEGF blockade followed by a low dose of 5-FU–treated MC38 colorectal cancers (n = 6–7 mice per group). ST: starting treatment; SD: switching drug. (C) Representative histological images of CD31⁺ blood vessels, CA9⁺ hypoxia, Ki67⁺ proliferating cells, and cleaved caspase-3⁺ apoptotic cells. Arrowheads point to proliferating (red signal) and apoptotic (green signal) cells. (D–G) Quantifications of CD31⁺ blood vessels, CA9⁺ hypoxia, Ki67⁺ proliferating cells, and cleaved caspase-3⁺ apoptotic cells in various agent-treated tumors (n = 6–8 random fields per group). Data are means ± SEM. *P < 0.05; **P < 0.01. ***P < 0.001. NS, not significant.