Related Experiment Video
Updated: Aug 19, 2026
Evaluation of the Efficacy of the H. pylori Protein HP-NAP as a Therapeutic Tool for Treatment of Bladder Cancer in an Orthotopic Murine Model
Published on: May 29, 2015
Ultrastructural localization of blood group antigen A in normal and neoplastic urothelium
Insights
Blood group antigen A distribution differs between normal and cancerous urothelial cells. Cancerous cells show reduced cell surface expression of blood group antigen A, indicating a processing defect.
Area of Science:
- Urothelial biology
- Immunohistochemistry
- Cancer research
Background:
- Blood group antigen A is present in the urinary tract's transitional epithelium.
- Neoplastic growths in the urinary tract may exhibit altered antigen expression.
Purpose of the Study:
- To investigate the subcellular localization of blood group antigen A.
- To compare antigen A distribution in normal versus neoplastic urothelial cells.
- To correlate antigen A expression with malignant behavior.
Main Methods:
- Transmission immuno-electronmicroscopy with an optimized immunogold procedure.
- Analysis of 65 tissue specimens from 50 blood group A1 patients.
- Quantitative assessment of antigen A reactions at subcellular levels.
Main Results:
- Blood group antigen A was detected in the glycocalyx, cytoplasmic processes, tubulovesicular structures, and Golgi complexes.
- Cell surface reactions for antigen A were significantly reduced in neoplastic (41%) compared to normal (88%) urothelial specimens.
- An inverse correlation exists between malignant behavior and cell surface antigen A expression.
Conclusions:
- Transitional cell carcinomas exhibit a quantitative defect in blood group antigen A processing, primarily affecting the cell surface.
- This defect may involve transport, glycosyltransferase activity, or antigen internalization.
- Altered cell surface antigen A expression could serve as a marker for urothelial tumor behavior.
Abstract:
The subcellular distribution of the blood group antigen A in the transitional epithelium of the urinary tract and its neoplastic growths was studied using transmission immuno-electronmicroscopy. Sixty-five tissue specimens from 50 blood group A1 patients were processed according to an immunogold procedure which was optimized for preservation of both antigen and ultrastructure. The reactions were stronger in the glycocalyx of the luminal surfaces and at the interdigitating cytoplasmic processes of the cells. In the intracellular compartment the reactions were associated with tubulovesicular membrane-bound structures and with the Golgi complexes. Secretory products, intra- or extra-cellular, were also positive. The greatest variability was noted in the cell surface reactions, which were positive in 88% of normal but only 41% of neoplastic urothelial specimens. An inverse correlation was found between malignant behaviour and cell surface, but not intracellular, reactions. We conclude that, in transitional cell carcinomas, there is a quantitative defect in the processing of substance A which affects predominantly the cell surface component and may involve either the transport-insertion steps, the plasma membrane-associated glycosyltransferases or internalization of blood group antigen A.
