Hormone Replacement Therapy and Breast Cancer Prognosis
Author Information
Author(s): Hall Per, Ploner Alexander, Bjöhle Judith, Huang Fei, Lin Chin-Yo, Liu Edison T, Miller Lance D, Nordgren Hans, Pawitan Yudi, Shaw Peter, Skoog Lambert, Smeds Johanna, Wedrén Sara, Öhd John, Bergh Jonas
Primary Institution: Karolinska Institutet, Stockholm, Sweden
Hypothesis
How does hormone-replacement therapy (HRT) influence gene expression profiles and breast cancer prognosis?
Conclusion
Post-menopausal HRT use is associated with a distinct gene expression profile that relates to better recurrence-free survival despite lower estrogen receptor levels.
Supporting Evidence
- HRT use was associated with an altered regulation of 276 genes.
- Expression profiles clustered ER-positive tumors into two molecular subclasses.
- Patients with HRT-associated gene expression had significantly better recurrence-free survival.
Takeaway
Women who use hormone therapy after menopause may have a different type of breast cancer that is less likely to come back, even if they have lower levels of a certain protein.
Methodology
Breast-cancer gene expression profiles were obtained using Affymetrix human genome U133A arrays, examining the relationship between HRT-regulated gene profiles, tumor characteristics, and recurrence-free survival in 72 postmenopausal women.
Potential Biases
Potential biases include closer medical surveillance for HRT users and the exclusion of women with preclinical breast-cancer lesions before starting hormone therapy.
Limitations
The study is non-randomized, which may introduce confounding factors related to both HRT use and tumor biology.
Participant Demographics
The study included 72 postmenopausal women with ER-positive tumors.
Statistical Information
P-Value
0.001
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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