To evaluate in vivo the immune response elicited by the treatment of MRP1-CD28 bi-specific aptamer, we treated B16-MRP1 tumor mice with the bi-specific aptamer as indicated in Figure 4A, and at day 15 mice were sacrificed to excise the tumor and assess T-lymphocyte infiltration by anti-CD3 immunohistochemistry (Figure 4B) and by qRT-PCR for the production of immuno-cytokines. The gene discussed is CD28; the disease is neoplasm.