ErbB2 (HER2/neu), a member of the epidermal growth factor (EGF) receptor tyrosine kinase family, is often (over)-expressed in breast cancer and other malignancies, such as brain tumors and sarcomas, but not on hematopoietic cells and may therefore represent an appropriate tumor antigen for targeted immune therapies [8]. Here, ERBB2 is linked to breast carcinoma.