ERBB2 and neoplasm: The 3 T3 transformation system has led to the discovery of many oncoproteins, including RAS family proteins, human epidermal growth factor receptor 1 (HER1/EGFR) and HER2 [54], and 3 T3 cells form very aggressive subcutaneous tumors that have been used as a standard model for tumor formation and metastases [55–58].