Table 3

Immunohistochemical analysis of GEO colon cancer xenografts after treatment with ZD1839

Mice bearing GEO tumor xenografts were treated as described in “Materials and Methods.” Briefly, 107 cells were injected, after being suspended in 200 μl of Matrigel, into the dorsal flank of 4–5-week-old nude mice on day 0. Treatment was started on day 7 after tumor cell injection, when tumor volume was ∼0.25 cm3. Mice were treated i.p. daily from day 1 to day 5 with the indicated doses of ZD1839 for 2 weeks. Analysis was performed on day 21 after tumor cell injection. Each group consisted of six mice. The percentage (± SD) of specifically stained GEO cancer cells for Ki67, TGF-α, bFGF, and VEGF was recorded. To determine the percentage of positive cells, at least 1000 cancer cells/slide were counted and scored. The number of microvessels for field (± SD) was measured using a monoclonal antibody raised against the human factor VIII-related antigen and was scored by averaging five field counts of three individual tumors for each group.
Dose of ZD1839 (mg/day)Tumor volume (cm3 ± SD)% positive cells (± SD)Factor VIII-related antigena
Ki67TGF-αbFGFVEGF
00.92 ± 0.1575 ± 1055 ± 845 ± 1050 ± 419 ± 3
1.250.68 ± 0.0850 ± 740 ± 625 ± 335 ± 28 ± 2
2.50.44 ± 0.0540 ± 525 ± 210 ± 215 ± 45 ± 1
3.750.31 ± 0.0735 ± 520 ± 25 ± 35 ± 14 ± 2
50.16 ± 0.0425 ± 25 ± 15 ± 13 ± 24 ± 1
  • a Figures for factor VII-related antigen are number of positively staining microvessels.