###Human: Is HER2 injection required after chemo and radiotherapy in breast cancer patient? ###Assistant: Hello. Can you give information regarding a few details? What was the stage? What was the histopathology report? What chemotherapy was received? If ER/PR and HER 2 was negative, then was FISH (fluorescence in-situ hybridization) done? If HER 2 is negative by FISH and histopathology, then HER 2 injection is not required. If HER 2 is positive, then if the disease is not metastatic then every three weekly injections for one year. If the disease is metastatic, then HER 2 injections are continued indefinitely till disease remains under control. I would be happy to help you if you have any further queries.