Is oestrogen receptor-beta a predictor of endocrine therapy responsiveness in human breast cancer?
The role of oestrogen receptor (ER) beta in human breast cancer remains unclear. However, it is now apparent that when considering ER beta in human breast cancer it is important to recognise two ER beta expressing groups, one in which ER beta is co-expressed with ER alpha and the other where ERbeta is expressed alone. Emerging data support different functions between ER beta when it is expressed alone and when it is co-expressed with ER alpha. With regard to the latter group (ER alpha +/ER beta +), there are now 9 out of 10 retrospective clinical outcome studies published, that support the hypothesis that increased expression of ER beta is associated with increased likelihood of response to endocrine therapy. The data strongly support undertaking prospective studies to determine if the addition of ERbeta to ER alpha is clinically beneficial and whether to include both ER beta and ER alpha when establishing clinically relevant cut-offs for defining ER status.
Murphy
Leigh C
LC
Manitoba Institute of Cell Biology, Department of Biochemistry and Medical Genetics, University of Manitoba, and Cancer Care Manitoba Winnipeg, Canada R3E 0V9. lcmurph@cc.umanitoba.ca
Watson
Peter H
PH
D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D016896:Treatment Outcome
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta