Since NEO-201 reacts specifically with variants of CEACAM-5 and CEACAM-6 expressed on different human carcinoma cell lines and tumor tissues, we evaluated the capacity of NEO-201 to bind to CEACAM-5 expressed on human cancer cell lines in order to determine whether NEO-201 was able to block the CEACAM-5-CEACAM-1 interaction and to restore the antitumor functionality of NK cells. Here, CEACAM1 is linked to cancer.