When cancer cells from various origins, including the prostate, breast, and lung, were treated with sublethal doses of 223Ra (4, 10, and up to 40 Gy), enhanced lysis mediated by CD8+ cytotoxic T lymphocytes that are specific for tumor-associated antigens such as MUC-1, brachyury, and carcinoembryonic antigen (CEA) was observed. Here, CEACAM5 is linked to neoplasm.