The present invention provides methods of treating, protecting against and inducing an immune response against a tumor or cancer, comprising the step of administering to a subject a recombinant Listeria strain. In one embodiment the present invention relates to a recombinant Listeria strain, said recombinant Listeria strain comprising a recombinant nucleic add, said nucleic add comprising a first open reading frame encoding a recombinant polypeptide comprising a first N-terminal fragment of an LLO protein fused to a heterologous antigen or fragment thereof, and wherein said recombinant nucleic add further comprises a second open reading frame encoding a mutant PrfA protein.
