Interestingly, the gene expression profiling of metastatic lung adenocarcinoma in the brain shows an increased expression of the receptor-binding cancer antigen expressed on SiSo cells (RCAS) and Fas ligand (FasL), which are present in neoplastic cells, induce apoptosis of NK/T cells, and play a role in immune evasion [23]. Here, FASLG is linked to cancer.