In addition, established cancer biomarkers, such as the carbohydrate antigen 125 (CA-125) [20], carbohydrate antigen 19.9 (CA19.9 or sialyl Lewisa) [21] and carcinoembryonic antigen (CEA) [22], are associated with elevated fucosylation levels during cancer progression. This evidence concerns the gene CEACAM5 and cancer.