Carbohydrate antigen 19-9 (CA 19-9) (CA 19-9)

Carbohydrate antigen 19-9 (CA 19-9), also known as sialyl-Lewis A (sLe^a), is a tetrasaccharide carbohydrate moiety typically found on the surface of glycoproteins and glycolipids. In healthy physiology, it is expressed at low levels in the ductal epithelium of the pancreas, biliary tract, and salivary glands, but it is significantly overexpressed in various gastrointestinal malignancies, most notably pancreatic ductal adenocarcinoma (Source: NIH, PubMed). Biologically, CA 19-9 serves as a high-affinity ligand for E-selectin, a cell adhesion molecule expressed on vascular endothelial cells, thereby facilitating the tethering and extravasation of tumor cells during the metastatic process (Source: Science). Beyond its role as a diagnostic and prognostic serum biomarker, recent research suggests that CA 19-9 is a functional driver of pancreatic inflammation and oncogenesis by activating EGFR signaling (Source: Science). Therapeutic strategies targeting CA 19-9 include monoclonal antibodies like MVT-5873, which aim to induce antibody-dependent cellular cytotoxicity (ADCC) or block E-selectin-mediated metastasis, as well as novel CAR-T cell therapies (Source: ClinicalTrials.gov). However, the clinical utility of CA 19-9 is limited by the fact that individuals with the Lewis-negative phenotype (approximately 5-10% of the population) lack the fucosyltransferase enzyme required to synthesize the antigen, leading to false-negative results (Source: StatPearls).

Other names

Sialyl-Lewis AsLe(a)Gastrointestinal Cancer AntigenGICASialyl-fucopentaose IICancer antigen 19-9

Monoclonal antibody-mediated antibody-dependent cellular cytotoxicity (ADCC), competitive inhibition of E-selectin binding to prevent metastasis, and CAR-T cell-mediated direct tumor cell lysis.