Sialyl-Tn (sTn) and Tn antigens (sTn/Tn)

Sialyl-Tn (sTn) and Tn antigens are truncated O-glycans that serve as prominent tumor-associated carbohydrate antigens (TACAs) (Pinho & Reis, 2015). They are formed due to the premature sialylation of the Tn antigen by sialyltransferases (such as ST6GalNAc-I) or mutations in the molecular chaperone Cosmc, which prevents normal glycan elongation (Ju et al., 2008). These antigens are overexpressed in a wide variety of epithelial cancers, including breast, colorectal, gastric, and ovarian carcinomas, while being virtually absent in healthy adult tissues (David et al., 1990). Their presence on the cell surface is often associated with poor prognosis, increased metastatic potential, and immune evasion through interactions with inhibitory receptors on immune cells (van Vliet et al., 2008). Therapeutic strategies targeting sTn and Tn include monoclonal antibodies, antibody-drug conjugates (ADCs), and CAR-T cell therapies, as well as glycan-based vaccines like Theratope designed to elicit an active immune response against tumor cells (Miles et al., 2011). The input name provided refers to binders (antibodies and lectins) rather than the target molecule itself.

Other names

Neu5Acα2-6GalNAcα1-O-Ser/ThrGalNAcα1-O-Ser/ThrCD175CD175sTumor-associated carbohydrate antigens (TACAs)TAG-72 (carbohydrate moiety)

Binding to truncated O-glycans on the tumor cell surface to induce immune-mediated cell death (ADCC/CDC), deliver cytotoxic payloads, or stimulate an active immune response via vaccination.