Estrogen receptor-beta mRNA is associated with adverse outcome in patients with breast cancer.
OBJECTIVE
Estrogen receptor (ER) is the prototype therapy predictive marker in oncology. The ER is now known to exist in two main forms with similar overall structure: ER-alpha and ER-beta. Both forms may be expressed in breast cancer. The aim of this study was to examine breast cancer outcome in relation to expression of ER-beta.


METHODS
In this investigation, we measured the expression of ER-alpha protein and ER-beta mRNA in 121 extracts of invasive breast cancer. Association of expression with clinical outcome was examined using Kaplan-Meier and Cox regression analyses.


RESULTS
While ER-alpha expression was associated with good patient outcome [hazard ratio (HR) for death from breast cancer 0.37; 95% confidence interval (CI) 0.17-0.84; p = 0.017], ER-beta predicted poor outcome (HR for death from breast cancer 2.49; 95% CI 1.10-5.63; p = 0.028).


CONCLUSIONS
Based on these findings, we conclude that ER-beta may have a different biological role from that of ER-alpha in breast cancer.
Markey
G C
GC
Conway Institute of Biomolecular and Biomedical Research, UCD School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
Cullen
R
R
Diggin
P
P
Hill
A D K
AD
Mc Dermott
E W
EW
O'Higgins
N J
NJ
Duffy
M J
MJ
D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D047628:Estrogen Receptor alpha / Q000235:genetics; D047629:Estrogen Receptor beta / Q000235:genetics*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D009361:Neoplasm Invasiveness / Q000235:genetics; D016016:Proportional Hazards Models; D012333:RNA, Messenger / Q000235:genetics*; D012044:Regression Analysis; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D012333:RNA, Messenger