In HER2 amplified breast cancers and colorectal cancers, an anti-HER2 monoclonal antibody Trastuzumab can be combined with another monoclonal antibody Pertuzumab (54, 55) or with an EGFR/HER2 dual kinase inhibitor Lapatinib (55, 56). Here, ERBB2 is linked to colorectal cancer.