Affiliations: [a] Department of Medicine, Division of Hematology and Oncology, Taipei Veterans General Hospital, Taipei, Taiwan | [b] Department of Medicine, Division of Transfusion Medicine, Taipei Veterans General Hospital, Taipei, Taiwan | [c] National Yang-Ming University School of Medicine, Taipei, Taiwan | [d] Institute of Public Health and School of Medicine, National Yang-Ming University, Taipei, Taiwan | [e] Department of Life Science, Fu-Jen University, New Taipei City, Taiwan
Correspondence:
[*]
Corresponding author: Tzeon-Jye Chiou, Department of Medicine, Division of Transfusion Medicine, Taipei Veterans General Hospital, No. 201 Shipai Road, Sec. 2, Taipei 11217, Taiwan. Tel.: +886 2 28757859; Fax: +886 2 28757874; E-mail:tjchiou@vghtpe.gov.tw
Abstract:
BACKGROUND:
The polymorphic CAG repeats of the androgen receptor (AR) gene have been
suggested to affect the risk of breast cancer, but the results are
controversial. In addition, the relationship between patients' CAG genotype
and the prognosis has not been investigated. OBJECTIVE: The purpose of this study is to access the association
between the polymorphic CAG repeats and the incidence and prognosis of
breast cancer. METHODS: One hundred and fifty-six breast cancer cases and 108 healthy controls from
Taipei Veteran General Hospital were enrolled. The length of CAG repeats was
analyzed among by means of PCR amplification. The logistic regression model
was used for cross-sectional analyses of prevalent breast cancer. Furthermore, we categorized the cases according to the average length of
both CAG alleles (CAGn ≥ 23 versus < 23). Outcomes were disease-free
survival and mortality. The Cox proportional hazards model and Kaplan-Meier
estimate were used for survival analysis. RESULTS:
The median age was 56 (51-64) and 46 (37-52) in breast cancer patients and
healthy controls, respectively. The median of CAGn was 22.5 (21.5-24) in
study group and 23 (21.5-24) in controls. Our study showed the length of
CAG repeats did not contribute to breast cancer or benign breast tumors (HR
1.01; 95% CI, 0.90-1.13). In the median follow-up of 6.59 years, we
found the CAGn ≥ 23 (n = 75) could be a poor prognosis (adjust HR,
3.08; 95% CI, 1.42-6.67, p = 0.004). CONCLUSION:
The CAG polymorphism is not associated with development of breast cancer,
but patients with more CAG repeats of the AR gene are prone to poor
prognoses.
Keywords: Prognostic factor, CAG repeat, CAG polymorphism, androgen receptor, breast cancer
