Polymorphisms in the androgen receptor CAG repeat sequence are related to tumour stage but not to ERG or androgen receptor expression in Malaysian men with prostate cancer
- Author:
Tan Jia Shin Jessica
1
Author Information
1. Departments of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Collective Name:Kien Chai Ong; Diana Bee-Lan Ong; Yuan Seng Wu; Azad Razack; Shanggar Kuppusamy; Jasmine Lim; Anthony Rhodes
- Publication Type:Journal Article
- Keywords:
Prostate cancer;
CAG repeat;
ERG;
ethnicity
- From:The Malaysian Journal of Pathology
2019;41(3):243-251
- CountryMalaysia
- Language:English
-
Abstract:
Introduction: Polymorphic expression of a CAG repeat sequence in the androgen receptor (AR) gene
may influence the activity of the AR and the occurrence of prostate cancer and the TMPRSS2-ERG
fusion event. Furthermore, this polymorphism may be responsible for the ethnic variation observed
in prostate cancer occurrence and expression of the ERG oncogene. We investigate the expression
of AR and ERG in the biopsies of Malaysian men with prostate cancer and in the same patients
relate this to the length of the CAG repeat sequence in their AR gene. Materials and Methods:
From a PSA screening initiative, 161 men were shown to have elevated PSA levels in their blood
and underwent prostatic tissue biopsy. DNA was extracted from the blood, and exon 1 of the AR
gene amplified by PCR and sequenced. The number of CAG repeat sequences were counted and
compared to the immunohistochemical expression of ERG and AR in the matched tumour biopsies.
Results: Of men with elevated PSA, 89 were diagnosed with prostate cancer, and 72 with benign
prostatic hyperplasia (BPH). There was no significant difference in the length of the CAG repeat in
men with prostate cancer and BPH. The CAG repeat length was not associated with; age, PSA or
tumour grade, though a longer CAG repeat was associated with tumour stage. ERG and AR were
expressed in 36% and 86% of the cancers, respectively. There was no significant association between
CAG repeat length and ERG or AR expression. However, there was a significant inverse relationship
between ERG and AR expression. In addition, a significantly great proportion of Indian men had
ERG positive tumours, compared to men of Malay or Chinese descent. Conclusions: CAG repeat
length is not associated with prostate cancer or expression of ERG or AR. However, ERG appears
to be more common in the prostate cancers of Malaysian Indian men than in the prostate cancers of
other Malaysian ethnicities and its expression in this study was inversely related to AR expression.
- Full text:5.2019my01018.pdf
