TP53 and neoplasm: Although the inherently greater chemo- and radio-sensitivity of EL4 lymphoma, which is reflected in its brisk and presumably P53-mediated apoptosis [35], may help to explain EL4 tumor eradication by the combination of chemotherapy and low doses of La-directed radioimmunotherapy, other factors may account for the reduced and differential sensitivity to this combination treatment of the carcinoma cell lines, LL2, in particular.