The present invention provides a composition for the treatment of a tumor, comprising: (i) allogeneic or xenogeneic tumor cells； and (ii) a pharmaceutically acceptable excipient. If two or more heterozygous individuals have the same cancer/tumor of the same or similar histological grade, then transplantation of tumor/cancer tissue/cells from one individual to another will not only induce rejection of the transplanted tissue/cancer, but will also increase the immunological awareness of the immune system to peptides shared between the tumors/cancers and other tumors possessing similar peptides.
