Figure 4. Tumor growth in mice in the drug vehicle treatment condition. Arrow represents formation of experimental housing conditions. Tumor weights (means ± standard error) from 11 to 18 days after tumor cell injection for drug vehicle-treated mice in the experimental housing conditions (n = 5, II; n = 9, IG; n = 6, GG; n = 6, GI). Tumor growth rates by 18 days after tumor cell injection (4 days after formation of experimental housing conditions): GI = GG > II = IG (p values <.05).