Several tumor antigens recognized by T cells have now been identified at the molecular level. Various mechanisms can account for their expression: activation of normally silent genes; point mutations; chromosome translocations; and post-translational modifications of proteins. This led to the notion that potential tumor-rejection antigens can be shared by a significant proportion of human tumors. This may have important implications in cancer immunotherapy, especially since tumors expressing a defined antigen can be identified on the basis of the expression of the relevant gene.
van der Bruggen, P., & Van den Eynde, B. (1992). Molecular definition of tumor-antigens recognized by T lymphocytes. Current Opinion in Immunology, 4(5), 608-612. https://doi.org/10.1016/0952-7915(92)90035-D (Original work published 1992)