Androgen receptor expression predicts breast cancer survival: The role of genetic and epigenetic events

Peters, Kate M., Edwards, Stacey L., Nair, Shalima S., French, Juliet D., Bailey, Peter J., Salkield, Kathryn, Stein, Sandra, Wagner, Sarah, Francis, Glenn D., Clark, Susan J. and Brown, Melissa A. (2012) Androgen receptor expression predicts breast cancer survival: The role of genetic and epigenetic events. BMC Cancer, 12 132: 1-10.

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Author Peters, Kate M.
Edwards, Stacey L.
Nair, Shalima S.
French, Juliet D.
Bailey, Peter J.
Salkield, Kathryn
Stein, Sandra
Wagner, Sarah
Francis, Glenn D.
Clark, Susan J.
Brown, Melissa A.
Title Androgen receptor expression predicts breast cancer survival: The role of genetic and epigenetic events
Journal name BMC Cancer  (ERA 2012 Listed)    (ERA 2010 Rank B)   Check publisher's open access policy
Publication date 2012-04-02
Sub-type Article
DOI 10.1186/1471-2407-12-132
Volume number 12
Issue number 132
ISSN 1471-2407
Start page 1
End page 10
Total pages 10
Place of publication London, U.K.
Publisher BioMed Central
Collection year 2013
Language eng
Formatted abstract Background: Breast cancer outcome, including response to therapy, risk of metastasis and survival, is difficult to predict using currently available methods, highlighting the urgent need for more informative biomarkers. Androgen receptor (AR) has been implicated in breast carcinogenesis however its potential to be an informative biomarker has yet to be fully explored. In this study, AR protein levels were determined in a cohort of 73 Grade III invasive breast ductal adenocarcinomas.

Methods: The levels of Androgen receptor protein in a cohort of breast tumour samples was determined by immunohistochemistry and the results were compared with clinical characteristics, including survival. The role of defects in the regulation of Androgen receptor gene expression were examined by mutation and methylation screening of the 5' end of the gene, reporter assays of the 5' and 3' end of the AR gene, and searching for miRNAs that may regulate AR gene expression.

Results: AR was expressed in 56% of tumours and expression was significantly inversely associated with 10-year survival (P = 0.004). An investigation into the mechanisms responsible for the loss of AR expression revealed that hypermethylation of the AR promoter is associated with loss of AR expression in breast cancer cells but not in primary breast tumours. In AR negative breast tumours, mutation screening identified the same mutation (T105A) in the 5'UTR of two AR negative breast cancer patients but not reported in the normal human population. Reporter assay analysis of this mutation however found no evidence for a negative impact on AR 5'UTR activity. The role of miR-124 in regulating AR expression was also investigated, however no evidence for this was found.

Conclusion: This study highlights the potential for AR expression to be an informative biomarker for breast cancer survival and sets the scene for a more comprehensive investigation of the molecular basis of this phenomenon.
Keyword Androgen receptor
Prognostic biomarker
Breast cancer
Gene regulation
Promoter methylation
Regulatory mutation
MiRNA
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

 
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Created: Wed, 30 May 2012, 10:05:11 EST by Lucy O'Brien on behalf of School of Chemistry & Molecular Biosciences