Since effector CD8+ T cells in the spleen could enhance the systemic immune defense against intracellular pathogens and tumors through the release of cytotoxic substances and exhausted CD8+ T cells may induce immune deterioration, we propose here that both an increase in the population of splenic CD8+ T cells and suppression of the exhaustion of splenic CD8+ T cells by repeated stimulation of D1-receptor-expressing neurons in the nucleus accumbens may contribute to tumor suppression through the facilitation of systemic immune systems. Here, CD8A is linked to neoplasm.