KLRK1 and neoplasm: On the one hand, low-dose LPS-stimulated macrophages can trigger NK cell proliferation, secretion of cytokines and increased killing of tumor targets via the 2B4/CD48 axis, while, on the other hand, macrophages activated with high doses of LPS expressed MICA and ULPBs, formed the so-called lytic synapse, and were lysed by NK cells via NKG2D (89).