ERBB2 and neoplasm: Therefore, most direct targets in oncology of this method include antigens and receptors expressed specifically by certain tumor cells (e.g., insulin-like growth factor 1 receptor—IGF1R; epidermal growth factor receptor—EGFR; human epidermal growth factor receptor 2—HER2), elements of the tumor microenvironment as well as altered cell metabolism or hypoxia, and extracellular acidosis caused by abnormal vasculature.