Previously, we developed an original technology for the production of cancer-specific monoclonal antibodies (CasMabs) and anti-glycopeptide mAbs (GpMabs) against membrane proteins.(9) We also developed sensitive and specific mAbs against several other membrane proteins using the same technology.(10–13) In this study, we developed anti-HER2 mAbs for use in flow cytometry, Western blot, and immunohistochemical analyses. Here, ERBB2 is linked to cancer.