A method for preventing or for treating cancer in a mammal, where the cancer cells express at least a part of an alpha fetoprotein molecule at the cell surface. The method comprises creating an immune response in the mammal to at least part of the amino acid sequence of an alpha fetoprotein molecule, where the immune response comprises activating alpha fetoprotein peptide specific T lymphocytes against the cancer cells, and where the part of the alpha fetoprotein molecule is selected from the group consisting of residues 137-145 of SEQ ID NO:2, and residues 325-334 of SEQ ID NO:2 and a combination of the preceeding.