ERBB2 and neoplasm: While Trastuzumab leads to HER2 internalisation, Pertuzumab prevents its dimerization [12, 13], and the addition of Pertuzumab to Trastuzumab and Docetaxel led to a significant improvement of pCR when compared to Trastuzumab and Docetaxel alone in HER2 + tumours (46% versus 29%) [10].