Combination of Trastuzumab and chemotherapy was found efficient in recurrent urothelial bladder carcinoma with HER2 GENE amplification in a case report as a second-line regimen, the patient got a clinically complete remission (CR) for 34 months after five cycles of trastuzumab 6 mg/kg every 3 weeks after a loading dose of 8 mg/kg and cisplatin 75 mg/m2 every 3 weeks (Jiang et al., 2020). The gene discussed is ERBB2; the disease is bladder transitional cell carcinoma.