ERBB2 and cancer: EGFR and HER2 belong to the type 1 tyrosine kinase receptor family consisting of four related receptors, forming dimers with each other, and are important for growth of various cancers.13 Several agents binding to EGFR and HER2 aimed to interfere with intracellular downstream signaling, and give therapy effects, are developed or are under development.14–18 Binders to the other receptors in the EGFR-family, i.e. HER3 and HER4, has so far not been introduced for clinical applications so we focus only on EGFR and HER2 in this study.