In our observations, CT26/HER2 tumor–bearing mice with splenomegaly had significantly higher systemic IFN-γ levels than the other animal groups (4T1.2/HER2 tumor-bearing mice with splenomegaly, 4T1.2/HER2 tumor-cured mice and naive control mice), again suggesting a possible role of IFN-γ in inhibiting CTL induction. This evidence concerns the gene ERBB2 and Splenomegaly.