KLRK1 and neoplasm: Differently, Mamessier et al. performed in vivo correlation studies demonstrating that in breast cancer patients decreased expression of activating NK cell receptors (NKp30, NKp46, NKG2D, DNAM-1) or cytotoxic molecules (GZMB) and increased levels of the inhibitory receptor NKG2A on NK cells were associated with high amount of TGF-β1 and PGE2 in tumor supernatants.