[{"from": "human", "value": "Describe this molecule. [C][C][=Branch1][C][=O][N][C@@H1][C@H1][Branch2][Ring1][#Branch2][C@H1][Branch2][Ring1][Branch1][C@H1][Branch1][S][O][C@@H1][Ring1][=Branch1][O][C][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O][N][C][O][O][O]"}, {"from": "gpt", "value": "The molecule is 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."}]