In certain embodiments, methods and compositions are provided for generating immune responses against tumor antigens such as a HER2/neu antigen or epitope. In particular embodiments there may be provided methods for constructing and producing recombinant adenovirus-based vector vaccines containing nucleic acid sequences encoding tumor antigens such as a HER2/neu antigen or epitope that allow for vaccinations in individuals with preexisting immunity to adenovirus.在某些實施例中,提供產生針對腫瘤抗原(諸如HER2/neu抗原或抗原決定基)之免疫反應的方法及組合物。在特定實施例中,可提供構築及產生基於腺病毒之重組載體疫苗之方法,該等疫苗含有編碼腫瘤抗原(諸如HER2/neu抗原或抗原決定基)之核酸序列,允許在具有預先存在腺病毒免疫性的個體中接種疫苗。