Given the high homology between human and murine Her2/neu [30], we propose that our human ECD/Her2 vaccine will also induce cross-reactive CTL against murine Her2/neu, rejecting transplantable tumors expressing murine Her2/neu, thus breaking tolerance against self-Her2/neu, as also proposed in other tumor models based on xeno-vaccinations [8,31]. The gene discussed is ERBB2; the disease is neoplasm.