Numerous tumor, epithelial, or stroma-derived growth factors bind with different affinities and specificities to the ErbB receptor family, including EGF, amphiregulin, and TGFα (EGFR-specific); betacellulin and epiregulin (specific for EGFR and ErbB4) (4); and the neuregulin/heregulin (HRG) family (specific for ErbB3 and ErbB4) (5). Here, ERBB4 is linked to neoplasm.