Tn tumor-associated carbohydrate antigen (Tn)

The Tn tumor-associated carbohydrate antigen is a truncated, immature O-glycan consisting of a single N-acetylgalactosamine (GalNAc) residue alpha-linked to a serine or threonine residue on a protein backbone (Source: Wikipedia, NIH). Under normal physiological conditions, this structure is a transient intermediate that is rapidly extended by the T-synthase enzyme into more complex O-glycans; however, in over 80% of human carcinomas, the Tn antigen is pathologically overexpressed due to mutations or silencing of the Cosmc chaperone or T-synthase (Source: Frontiers in Immunology, 2025). This 'pancarcinoma' antigen is virtually absent in healthy adult tissues, making it a highly specific target for oncology (Source: MDPI, 2024). Biologically, the Tn antigen promotes tumor progression by enhancing cell motility, inducing the epithelial-mesenchymal transition (EMT), and activating oncogenic signaling cascades such as the EGFR/FAK pathway (Source: NIH). It also plays a critical role in immune evasion by binding to the macrophage galactose-type lectin (MGL) on myeloid cells, which creates an immunosuppressive microenvironment (Source: Frontiers in Immunology). Current therapeutic strategies include monoclonal antibodies, antibody-drug conjugates (ADCs), and CAR-T cell therapies designed to exploit the high differential expression of Tn between malignant and healthy cells (Source: PatSnap, 2024).

Other names

Tn antigenGalNAc-alpha-O-Ser/ThrThomsen-nouveau antigenCD175Tumor-associated Tn antigenN-acetylgalactosamine-alpha-O-serine/threonine

Therapeutic agents targeting the Tn antigen utilize several mechanisms: monoclonal antibodies (e.g., 5E5) induce tumor cell death via antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC); CAR-T cells (e.g., huMNC2-CAR44) provide direct T-cell mediated lysis of Tn-expressing cells; and vaccines (e.g., MAG-Tn3) stimulate the production of high-affinity anti-Tn antibodies. Additionally, blocking the Tn antigen can disrupt oncogenic signaling through the EGFR/FAK pathways and prevent immune suppression by inhibiting the interaction between Tn and the macrophage galactose-type lectin (MGL) receptor on immune cells (Source: NIH, Frontiers in Immunology).