Cancer Res Treat.  2012 Mar;44(1):50-56.

Correlation of AR, EGFR, and HER2 Expression Levels in Prostate Cancer: Immunohistochemical Analysis and Chromogenic In Situ Hybridization

• Baek KH
• Hong ME
• Jung YY
• Lee CH
• Lee TJ
• Park ES
• Kim MK
• Yoo JH
• Lee SW

Abstract

PURPOSE
The androgen receptor (AR) plays a central role in prostate cancer. Evidence from several groups indicates that epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) may enhance AR activity in prostate cancer cell lines. This study was designed to investigate the protein expression of AR, EGFR, and HER2 and to determine whether the EGFR and HER2 genes are amplified in prostate cancer tissues.
MATERIALS AND METHODS
The protein expression levels of AR, EGFR, and HER2 in a tissue microarray block of 66 prostate cancer samples were investigated by immunohistochemical analysis and chromogenic in situ hybridization was used to determine whether the EGFR and HER2 genes were amplified in these tissues.
RESULTS
The AR and EGFR proteins were expressed in 59.1% and 40.9% of prostate cancers, respectively, but their expression levels were not significantly associated with clinicopathologic factors. Of the cases in which tissues were negative for EGFR protein expression, 69.2% were positive for AR protein expression; however, AR protein expression was significantly reduced (44.4%) in tissues in which EGFR protein was expressed. HER2 expression was detected in only 1 case (1.5%). No amplification of the EGFR or HER2 genes was found in prostate cancer specimens.
CONCLUSION
This study was limited by small number of subjects, but it can still be inferred that the expression levels of the AR and EGFR proteins are inversely correlated in prostate cancer patients. The potential utility of EGFR and HER2 as prognostic factors or therapeutic targets warrants further study.

Keyword

Prostatic neoplasms; Androgen receptors; Epidermal growth factor receptor; HER2

MeSH Terms

Cell Line
Genes, erbB-2
Humans
In Situ Hybridization
Prostate
Prostatic Neoplasms
Proteins
Receptor, Epidermal Growth Factor
Receptor, erbB-2
Receptors, Androgen
Proteins
Receptor, Epidermal Growth Factor
Receptor, erbB-2
Receptors, Androgen

Figure

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  Fig. 1 Expression of androgen receptor. (A) Positive immunoreactivity in benign prostatic glands and stroma (AEC staining, ×40). (B) Strong immunoreactivity in prostatic adenocarcinoma (AEC staining, ×400).

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  Fig. 2 Expression of epidermal growth factor receptor. (A) Strongly positive immunoreactivity in benign prostatic glands and weakly positive immunoreactivity in prostatic adenocarcinoma (AEC staining, ×40). (B) Strong membrane staining in prostatic adenocarcinoma (AEC staining, ×400).

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  Fig. 3 Expression of human epidermal growth factor receptor 2. (A) Negative immunoreactivity in normal prostatic glands and prostatic adenocarcinoma (AEC staining, ×40). (B) Weakly membrane staining in prostatic adenocarcinoma (AEC staining, ×400).

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  Fig. 4 Epidermal growth factor recptor (EGFR) (A) and human epidermal growth factor recptor 2 (HER2) (B) gene amplification examined by chromogenic in situ hybridization. One or 2 signals are visible in nuclei of adenocarcinoma cells. There is no evidence of gene amplification (CISH staining, ×400).

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