FasL expression during progression of colorectal carcinogenesis and its potential prognostic implication

Background: Fast expressing tumor cells maybe able to eliminate activated T-cells via Fas/FasL induced apoptosis. Methods: We analysed by means of immunhistchemistry the Fast protein expression in colorectal normal mucosa, transitional mucosa, adenomas, carcinomas and their liver metastases on paraffin tissue sections of 171 patients with known follow-up Results: Adenomas expressed Fast more strongly than the transitional mucosa. This expression was further increased in carcinomas, with no differences during the progression of the tumor stage. However, Fast expression in the transitional mucosa showed a significant increase during the progression of the primary carcinoma and was of prognostic relevance in univariate analysis. Conclusion: This finding suggests a paracrine regulation of the Fast-expression in the transitional mucosa through the carcinoma cells.