ERBB2 and neoplasm: As we previously observed that immune cells from at least 3 of the 5 4T1.2/HER2 tumor-bearing and tumor-cured mice showed a more than 2-fold increase in IFN-γ production in response to the HER2 peptides HER263–71 and HER2342–350 relative to the response to the control peptides, we next examined whether 4T1.2/HER2 tumor-bearing mice might have CTL lytic responses to these two peptides.