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Laser-capture Microdissection of Human Prostatic Epithelium for RNA Analysis
Published on: November 26, 2015
Decreased annexin I expression in prostatic adenocarcinoma and in high-grade prostatic intraepithelial neoplasia
K T Patton1, H M Chen, L Joseph
1Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA.
Aims:
To analyse annexin I expression in prostatic carcinoma. Annexin I belongs to a family of structurally related calcium and phospholipid-binding proteins implicated in signal transduction, DNA replication, cell proliferation and apoptosis. The decreased expression of annexin I, II and VII proteins has been reported in different types of cancer.
Methods And Results:
Using immunohistochemistry, we analysed annexin I expression in 77 cases of prostatic adenocarcinoma (Gleason score 6, N = 40; Gleason scores 7-8, N = 27; and Gleason scores 9-10, N = 10) and high-grade prostatic intraepithelial neoplasia (PIN, N = 50). Immunoreactivity of annexin I in tumour cells was evaluated as negative (< 5% of cells), focally positive (5-25% of cells) or positive (> 25% of cells). In contrast to positive staining in adjacent benign prostatic epithelium, annexin I expression was decreased (focally positive) in 76% of cases of high-grade PIN (P < 0.0001) and was decreased or absent in 81% of prostatic adenocarcinomas (P < 0.0001). Annexin I expression in all higher grade tumours (Gleason scores 7-10) was only focally positive or absent.
Conclusions:
Expression of annexin I inversely correlates with the increasing histological grade of prostatic adenocarcinoma. By showing a progressive loss of annexin I expression in high-grade PIN, intermediate-grade and high-grade cancer, our findings suggest that the loss of annexin I expression occurs early in prostatic tumorigenesis and becomes more prominent throughout tumour progression. The loss of expression of annexin I may serve as a useful marker of prostate cancer development and progression.
Insights
Decreased expression of annexin I is observed in high-grade prostatic intraepithelial neoplasia and prostate cancer. This loss of annexin I correlates with tumor grade, suggesting its role in prostate cancer progression.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Annexin I is a calcium and phospholipid-binding protein involved in cell signaling, proliferation, and apoptosis.
- Reduced expression of annexin I, II, and VII has been linked to various cancers.
- Prostate cancer is a significant health concern with a need for better diagnostic and prognostic markers.
Purpose of the Study:
- To investigate the expression levels of annexin I in prostatic adenocarcinoma.
- To determine the correlation between annexin I expression and the histological grade of prostate cancer.
- To evaluate annexin I as a potential biomarker for prostate cancer development and progression.
Main Methods:
- Immunohistochemistry was employed to analyze annexin I expression in 77 prostate adenocarcinoma samples and 50 high-grade prostatic intraepithelial neoplasia (PIN) samples.
- Prostate cancer samples were categorized by Gleason scores (6, 7-8, 9-10).
- Annexin I immunoreactivity was quantified as negative, focally positive, or positive based on the percentage of positive cells.
Main Results:
- Annexin I expression was significantly decreased in high-grade PIN (76% of cases, P < 0.0001) and prostate adenocarcinomas (81% of cases, P < 0.0001) compared to adjacent benign prostatic epithelium.
- A progressive loss of annexin I expression was observed with increasing Gleason scores.
- Higher-grade tumors (Gleason scores 7-10) showed only focal or absent annexin I expression.
Conclusions:
- Annexin I expression inversely correlates with the histological grade of prostate adenocarcinoma.
- The progressive loss of annexin I during tumorigenesis suggests its early involvement in prostate cancer development.
- Loss of annexin I expression may serve as a valuable marker for prostate cancer diagnosis and progression monitoring.
