Fig. 4.

Effects of interferons on tumor growth inhibition. Mice were inoculated with 5 × 10⁵ colon 26 adenocarcinoma cells in RPMI 1640 with 10% FBS subcutaneously. Seven days after tumor cell inoculation, the tumor size was measured. The mice were then treated with different interferons by intratumoral injection. IFN-α was injected every day for 3 weeks, the others were injected at 1 week, 2 weeks and 3 weeks. Tumor volume was estimated for the largest (a) and smallest (b) diameter, and the tumor volume was calculated using V= ab²/2. Each point represents the mean ± SD. ^*Significantly different from control (p < 0.05). ^**Significantly different from control (p < 0.01).