ERBB2 and neoplasm: For this test, we evaluated the ability of immune cells isolated from tumor (CT26/HER2 vs. 4T1.2/HER2)-bearing mice to produce IFN-γ in response to the HER2 class I peptides, HER263–71, HER2342–350, HER2440–448, HER2553–561, HER2780–788 and HER2907–915.