TLR4 and neoplasm: Because resistance to the metastasis of tumor cells is dependent on cytokines, macrophages, NK cells, and gdT cells (20–23), we investigated the anti-tumor activity of RAP99-LPS using a B16F1 lung metastasis model and found that RAP99-LPS treatment significantly suppressed the metastasis, though we did not show if this suppressive effect is mediated by TLR4.