RC48 has demonstrated clinical benefits in the treatment of gastric cancer and urothelial carcinoma.A real-world retrospective study (24) included 23 patients with advanced solid tumours such as breast cancer, gastric cancer, colorectal cancer, and bladder cancer, with at least Her-2 immunohistochemistry 1+ expression and failure after at least one systemic chemotherapy. This evidence concerns the gene ERBB2 and breast cancer.