Japanese Journal of Clinical Oncology Advance Access originally published online on October 11, 2007
Japanese Journal of Clinical Oncology 2007 37(11):820-828; doi:10.1093/jjco/hym114
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2007 Foundation for Promotion of Cancer Research
Expression of Estrogen Receptor β Wild-type and its Variant ERβcx/β2 is Correlated with Better Prognosis in Breast Cancer
1 Oncology, Immunology and Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya
2 Breast and Endocrine Surgery, Kumamoto University, Kumamoto, Japan
For all reprints and correspondence: Hiroko Yamashita, Oncology, Immunology and Surgery, Nagoya City University Graduate School of Medical Sciences, Kawasumi 1, Mizuho-ku, Nagoya 467-8601, Japan. E-mail: hirokoy{at}med.nagoya-cu.ac.jp
Received May 7, 2007; accepted July 23, 2007
Background: The clinical value of estrogen receptor (ER) β and its variants has been investigated. However, reported results have frequently been discordant.
Methods: We investigated mRNA and protein expression of ERβ wild type (ERβ1) and its variant, ERβcx/β2, by quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry in 150 breast cancer tissues, and analyzed association between their expression and clinicopathological factors and prognosis.
Results: ERβ1 mRNA expression was significantly correlated with progesterone receptor expression and low histological grade. ERβ1 protein expression was significantly correlated with small tumor size, negative lymph node status and low histological grade. ERβcx/β2 protein expression was significantly correlated with ER
expression and low histological grade. Patients with high expression of ERβ1 or ERβcx/β2 had a significantly better disease-free and overall survival than those with low expression. In multivariate analysis, ERβcx/β2 mRNA expression was identified as a prognostic factor in disease-free and overall survival.
Conclusion: Our results indicate that ERβcx/β2 mRNA expression is an independent prognostic factor in breast cancer. ERβ expression status, both wild-type and the variant cx/β2, might represent significant predictors of breast cancer prognosis.
Key Words: breast cancer estrogen receptor β prognosis
Abbreviations: ER, estrogen receptor; IHC, immunohistochemistry; PgR, progesterone receptor; RT-PCR, reverse transcriptase-polymerase chain reaction.