Xenograft models of both trastuzumab-sensitive and resistant BT474 ErbB2 positive breast tumours also show that trastuzumab plus a γ-secretase inhibitor (MRK-003) could completely prevent tumour re-growth in sensitive cells after treatment withdrawal and reduce tumour growth in trastuzumab resistant BT474 xenografts [12]. Here, ERBB2 is linked to neoplasm.