Lymphocyte function-associated antigen-1 (LFA-1) is located on the membrane of CIKs and can specifically recognize intercellular adhesion molecule-1 (ICAM-1), which is highly expressed in tumour cells, thereby mediating tumour cell death (89–91), which means that the downregulation of ICAM-1 may contribute to cancer cell protection against the killing effect. The gene discussed is ICAM1; the disease is cancer.