ERBB2 and breast cancer: To further validate the specificity of the anti-tumor immunity and associated T cell responses upon T-PNU treatment, we next re-challenged T-PNU ADC treated animals with complete tumor regression by injection of the same tumor cells expressing hHER2, i.e. EMT6-hHER2, or the parental EMT6-WT or another murine breast cancer cell lineTS/A Thy1.1, both of which not expressing the human HER2 antigen (Fig. 6a).