We have developed cancer-specific mAbs (CasMabs) against various tumor antigens, including HER2 (clones H2Mab-214 [79] and H2Mab-250 [80]), and reported the antitumor effect in mouse xenograft models using recombinant mouse IgG2a or human IgG1 mAbs [71,72]. Here, ERBB2 is linked to cancer.