Although cytokines have been considered as cancer biomarkers hitherto, few other glycoproteins, typically carcinoembryonic antigen (CEA) and tissue inhibitor of metalloproteinase 1 (TIMP1), are involved in cellular adhesion that is commonly produced in gastrointestinal tissue and their abnormal levels are reported in serum of lung, colorectal, and breast cancer [35,36]. This evidence concerns the gene CEACAM5 and breast cancer.