In previous studies, we showed that NEO-201 specifically recognizes a tumor-associated variant of CEACAM5 and CEACAM6, which is not expressed in normal tissues, and proved that NEO-201 binds to both mammalian-expressed recombinant human CEACAM5 and CEACAM6 but not to CEACAM1 or CEACAM8 by ELISA [2,23]. Here, CEACAM5 is linked to neoplasm.