Tn Antigen

**Semantic type:** Amino Acid, Peptide, or Protein|Immunologic Factor

**Definition:** A protein antigen that is comprised of the monosaccharide N-acetylgalactosamine (GalNAc) bound to serine or threonine by O-linked glycosylation. Aberrant expression of Tn antigen by all blood cell lineages is associated with a rare hematological disorder called Tn-syndrome. Increased expression of this monosaccharide modification is also associated with some cancers and this antigen is being investigated for use as either a biomarker or therapeutic target for these associated malignancies.

**Synonyms:** - CD175 - Tn