Another cancer hallmark is the tumour cell production of glycoproteins and proteoglycans with altered glycosylation (e.g., cancer antigen 19-9 and 125, carcinoembryonic antigen, prostate-specific antigen and alpha-fetoprotein) secreted or shed from the cell membranes into the bloodstream where they may serve as tumour-associated biomarkers) [80]. Here, CEACAM5 is linked to neoplasm.