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Immunohistochemical analysis of Fas and FLIP in prostate cancers
Su Young Kim1, Sang Yong Song, Min Sung Kim
1Department of Pathology, College of Medicine, the Catholic University of Korea, Seoul, Korea.
Abstract:
Fas-mediated apoptosis is considered a principal pathway for apoptosis induction in normal and cancer cells. Expression of Fas has been reported in prostate tissues several times, but the data were not consistent. Expression of FLICE-like inhibitory protein (FLIP), an inhibitor of Fas-mediated apoptosis, has not been studied by immunohistochemistry in prostate tissues. The aim of this study is to explore whether alterations of Fas and FLIP expression occur in prostate cancer tissues. We analyzed the expression of Fas and FLIP in 107 prostate adenocarcinoma tissues by immunohistochemistry using a tissue microarray approach. Normal glandular cells of the prostates strongly expressed both Fas and FLIP proteins. Prostate intraepithelial neoplasm also showed a strong Fas immunoreactivity. Fas expression was strongly positive in 60 cancers (56.1%), but the remaining 47 cancers showed no (6.5%) or markedly decreased (37.4%) Fas immunostaining compared with the normal glandular cells of the same patients. By contrast, FLIP expression was strong in most (103/107; 96.3%) of the cancers, and only four cancers (3.7%) showed decreased immunoreactivities compared with the normal cells. The decreased expression of Fas was not associated with pathologic characteristics, including FLIP expression, size of the cancers, age, Gleason score and stage. The decreased expression of Fas in a large fraction of prostate cancers compared with their normal cells suggested that loss of Fas expression might play a role in tumorigenesis in some prostate cancers possibly by inhibiting apoptosis mediated by Fas.
Insights
Fas-mediated apoptosis is crucial for cell death. This study found decreased Fas expression in many prostate cancers, suggesting it may contribute to tumor development by hindering apoptosis.
Area of Science:
- Oncology
- Cell Biology
- Molecular Pathology
Background:
- Fas-mediated apoptosis is a key pathway for cell death in normal and cancerous cells.
- Previous studies on Fas expression in prostate tissues yielded inconsistent results.
- FLICE-like inhibitory protein (FLIP), an inhibitor of Fas-mediated apoptosis, has not been extensively studied in prostate tissues via immunohistochemistry.
Purpose of the Study:
- To investigate alterations in Fas and FLICE-like inhibitory protein (FLIP) expression in prostate cancer tissues.
- To determine the correlation between Fas and FLIP expression and prostate cancer development.
Main Methods:
- Immunohistochemistry was used to analyze Fas and FLIP expression.
- A tissue microarray approach was employed on 107 prostate adenocarcinoma tissues.
- Expression levels were compared between cancerous tissues, prostate intraepithelial neoplasm, and normal prostate glandular cells.
Main Results:
- Normal prostate cells and prostate intraepithelial neoplasm showed strong expression of both Fas and FLIP.
- Fas expression was significantly decreased or lost in 43.9% of prostate cancers compared to normal cells.
- FLIP expression remained strong in the vast majority (96.3%) of prostate cancers.
Conclusions:
- A significant decrease in Fas expression occurs in a substantial portion of prostate cancers.
- The loss of Fas expression in prostate cancer may play a role in tumorigenesis by inhibiting Fas-mediated apoptosis.
- FLIP expression is generally maintained in prostate cancers, suggesting a potential compensatory mechanism or independent pathway in cancer progression.
