Methods for the treatment of patients with HER2-positive, HER2-amplified and / or HER2-mutated advanced cancer by administration of pertuzumab plus trastuzumab are disclosed. In one aspect, the cancer is advanced HER2-positive, HER2-amplified and / or HER2-mutated colorectal, biliary, bladder, urothelial, salivary, lung, pancreatic, ovarian, prostate, or skin cancer. In another aspect, the cancer is HER2-positive, HER2-amplified and / or HER2-mutated colorectal, biliary, bladder, urothelial, salivary, lung, pancreatic, ovarian, prostate, or skin cancer that is refractory to one or more other treatment regimens.