In the present study, we found that NKG2DL expression levels determined the rejection of allogeneic tumors from breast cancer cells, melanoma cells and glioma cells at the early stage after being inoculated in mice, and NKG2DL up-regulation led to the early rejection by activating NKG2D+ NK cells and NKG2D+ CD8+ T cells. The gene discussed is KLRK1; the disease is melanoma.