We compared the response to anti-PD1/PD-L1 antibody therapy in two different lines of tumor mice (WAP-T and WAP-TNP mice, respectively) immunologically differing only in the expression of a single T-cell epitope in their major tumor antigen: WAP-T and WAP-TNP mice contain both as transgene the SV40 early gene region under control of the whey acidic protein (WAP) promoter, which upon induction codes for SV40 early proteins, with T-antigen being the major tumor antigen. The gene discussed is CD274; the disease is neoplasm.