MICA and neoplasm: Ziani et al showed that the increasing secretion of matrix metalloproteinases (MMPs) by CAFs in the melanoma tumour microenvironment could reduce the expression of MICA/B, therefore further decreasing the cytotoxic activity of NK cells to melanoma cancer cells which depended on NKG2D.65 Compared to the normal endometrial fibroblasts (NEFs), the expression of poliovirus receptor (PVR) was downregulated in CAFs.66 PVR is expressed on the cell surface of NEFs and CAFs, which is a ligand of the NK activating receptor DNAX accessory molecule‐1 (DNAM‐1).