Experiments performed in vivo using immune cell depletion antibodies or agents showed that in the S100 monotherapy group, blockage of CD8+ T cells resulted in the significant inhibition of tumor growth; whereas CD4+ T cells, macrophages, and NK cells elicited minimal effects, suggesting that S100 exerted an anti-tumor immunity which was primarily dependent upon CD8+ T cells. The gene discussed is CD8A; the disease is neoplasm.