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Short term neoadjuvant androgen deprivation therapy does not affect prostate specific membrane antigen expression in
S S Chang1, V E Reuter, W D Heston
1George M. O'Brien Urology Research Center, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Cancer
|January 21, 2000
Summary
Short-term androgen deprivation therapy (ADT) does not alter prostate specific membrane antigen (PSMA) expression in prostate cancer. However, prostate cancer and high-grade PIN show higher PSMA levels than benign tissue, with PM2J004.5 being a more sensitive marker.
Area of Science:
- Oncology
- Urology
- Immunohistochemistry
Background:
- Prostate specific membrane antigen (PSMA) is a transmembrane glycoprotein highly expressed in prostate carcinoma and benign prostate secretory-acinar epithelium.
- Previous studies suggest increased PSMA expression in prostate cancer cell lines under androgen deprivation and in androgen-independent tumors.
- This study investigated the impact of short-term androgen deprivation on PSMA expression in prostate cancer specimens.
Purpose of the Study:
- To evaluate the effect of 3-month neoadjuvant androgen deprivation therapy (ADT) on PSMA expression in prostate carcinoma.
- To compare the sensitivity of two anti-PSMA monoclonal antibodies (mAbs), 7E11 and PM2J004.5, in detecting PSMA in prostate tissues.
- To assess PSMA expression levels in benign epithelium, high-grade prostatic intraepithelial neoplasia (PIN), and prostate carcinoma.
Main Methods:
- Patients with localized prostate cancer were randomized to either neoadjuvant ADT followed by radical prostatectomy (ADT/RP) or radical prostatectomy (RP) alone.
- Formalin-fixed, paraffin-embedded prostate sections were immunostained using anti-PSMA mAbs 7E11 and PM2J004.5.
- Staining intensity and percentage of positive cells were recorded and compared between mAbs and treatment groups.
Main Results:
- Both mAbs stained benign epithelium, high-grade PIN, and prostate carcinoma.
- PM2J004.5 demonstrated significantly higher cell percentage and intensity compared to 7E11 in benign epithelium and prostate carcinoma.
- High-grade PIN and prostate carcinoma showed significantly higher PSMA staining than benign epithelium, irrespective of treatment group.
Conclusions:
- Short-term neoadjuvant ADT does not influence PSMA expression in prostate tissues.
- Prostate carcinoma and high-grade PIN exhibit elevated PSMA levels compared to benign prostate secretory-acinar epithelium.
- The PM2J004.5 mAb is a more sensitive immunohistochemical marker for prostate carcinoma detection in formalin-fixed, paraffin-embedded tissues than the 7E11 mAb.