MICA and melanoma: We also demonstrated that melanoma-associated CAFs decrease the sensitivity of melanoma tumor cells to NK cell-mediated killing through the secretion of MMPs which cleave MHC class I-related chain (MIC)-A and MIC-B [two ligands of NK group 2D (NKG2D)], at the surface of the tumor cells and consequently decrease both NKG2D-dependent cytotoxic activity of NK and their secretion of IFNγ [140].