Numerous monoclonal antibodies (mAbs) directed against various cancers (gastric cancer, colonic and small cell adenocarcinomas, lung squamous carcinoma) and cancer cell lines (leukemia HL-60, SCLC) were shown to react with the Lewis X (Lex) determinant similarly to a mAb directed against the stage-specific embryonic antigen-1 (SSEA-1) [11,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. Here, FUT4 is linked to gastric cancer.