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Tumor-associated glycoprotein (TAG-72) expression in ulcerative colitis
A Thor1, S H Itzkowitz, J Schlom
1Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston.
International Journal of Cancer
|May 15, 1989
Summary
Monoclonal antibody B72.3 targets tumor-associated glycoprotein 72 (TAG-72). TAG-72 expression increases with dysplasia and cancer in ulcerative colitis, but active inflammation complicates its use for colon cancer detection.
Area of Science:
- Gastroenterology
- Oncology
- Immunohistochemistry
Background:
- Monoclonal antibody (MAb) B72.3 targets tumor-associated glycoprotein 72 (TAG-72), a high-molecular-weight antigen.
- TAG-72 expression is utilized in colon cancer diagnostics and therapeutics.
- Previous studies suggest TAG-72 expression may be elevated in inflammatory bowel disease, specifically ulcerative colitis.
Purpose of the Study:
- To evaluate TAG-72 expression in colonic specimens from ulcerative colitis patients with varying degrees of epithelial abnormalities.
- To assess the correlation between TAG-72 expression, disease duration, and disease activity in ulcerative colitis.
- To determine the clinical utility of TAG-72 for colon cancer detection in ulcerative colitis patients.
Main Methods:
- Immunohistochemical analysis of TAG-72 expression using MAb B72.3.
- Study included 117 colonic specimens from 56 ulcerative colitis patients (ranging from reactive atypia to carcinoma) and 11 inflammatory controls.
- Specimens were paraffin-embedded and formalin-fixed; patient data included disease duration and activity (active vs. quiescent).
Main Results:
- TAG-72 expression was similar in controls and non-dysplastic epithelia, but increased significantly with low-grade dysplasia, high-grade dysplasia, and carcinoma.
- Staining patterns varied with dysplasia grade: focal perinuclear in low-grade, pancytoplasmic in high-grade, and cytoplasmic/extracellular in invasive disease.
- Active disease showed more TAG-72 immunoreactivity than quiescent disease. In quiescent disease, TAG-72 expression correlated with disease duration; this correlation was absent in active disease.
Conclusions:
- TAG-72 expression correlates with the dysplasia-to-carcinoma sequence in ulcerative colitis.
- The frequent expression of TAG-72 in actively inflamed colonic mucosa may limit its utility for colon cancer detection via serological assays or in vivo radiolocalization in ulcerative colitis patients.
- TAG-72 expression patterns in ulcerative colitis depend on disease activity and duration, influencing its diagnostic applicability.