Antitumor efficacy of chitosan/IL-12. CEA.Tg mice were inoculated with MC32a tumors on day 0 and treated i.t. on days 7, 14, and 21. Individual tumor growth curves for mice treated with (A) PBS, (B) chitosan solution alone, (C) 1 µg IL-12 alone, or (D) 1 µg chitosan/IL-12. Chitosan/IL-12-treated tumors were significantly smaller than IL-12 treated tumors (P<0.05 from day 14 to 32); (E) overall survival of mice receiving i.t. immunotherapy with DPBS (■), chitosan (▲), 1 µg IL-12 (●), or 1 µg chitosan/IL-12 (○). The median survival of chitosan/IL-12-treated mice is significantly greater than IL-12-treated mice (P=0.0004; log-rank test). Figures represent a compilation of 2 separate experiments. (F) C57BL/6 mice were inoculated with Panc02 tumors on day 0 and treated i.t. on days 10 and 17 with DPBS (■), chitosan (▲), 1 µg IL-12 (●), or 1 µg chitosan/IL-12 (○). Each data point represents mean tumor volume ± SEM from 5 mice. * indicates P < 0.05 vs. IL-12.