CA19.9 antigen circulating in the serum of colon cancer patients: Where is it from?

Lydia Mare, Anna Caretti, Riccardo Albertini, Marco Trinchera

Research output: Contribution to journalArticle

Abstract

CA19.9 antigen is a glycoprotein present in human serum and found elevated in various diseases. It is intensively studied since long time as a potential marker for managing cancers of the gastrointestinal tract, but its reliability is widely accepted only for pancreatic cancers. Here, we focused on the tetrasaccharide epitope (NeuAcα2-3Galβ1-3[Fucα1-4]GlcNAc) sialyl-Lewis a studying the biosynthesis, expression, and secretion in colon cancers and related cancer cell lines. We found that the β1,3 galactosyltransferase β3Gal-T5, responsible for sialyl-Lewis a synthesis, is dramatically reduced in colon adenocarcinomas, in terms of both transcript and enzyme activity levels. Moreover, no or very faint antigen is detectable in colon cancer homogenates, by dot-blot or enzyme immunoassay, while it is commonly evident in sera from different patients. In cancer cell lines synthesizing CA19.9, the amount of antigen secreted is proportional to that expressed on the cell surface, and depends on appreciable levels of β3Gal-T5, which appear much higher than those measured in colon cancer specimens. Since colon cancers appear unable to synthesize relevant amount of CA19.9, we suggest that the antigen circulating in the serum of colon cancer patients may have a different and more complex origin than expected so far.

Original languageEnglish
Pages (from-to)792-797
Number of pages6
JournalInternational Journal of Biochemistry and Cell Biology
Volume45
Issue number4
DOIs
Publication statusPublished - Apr 2013

Keywords

  • Carbohydrate antigen
  • Colon cancer
  • Gastrointestinal tract
  • Hepatobiliary system
  • Tumor marker

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology

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