Increased ERα and ERβ bioactivity linked to breast cancer presence
MedWire News: High serum bioactivities of estrogen receptor (ER) α and βare better predictors of breast cancer than estrogen concentration, a study suggests.
Estrogens have a vital role in the development of breast cancer; however, most studies have assayed endogenous estrogen levels rather than bioactivity. Martin Widschwendter (University College London, UK) and colleagues independently measured the bioactivities of ERα and ERβ using a receptor estrogen-responsive element (ERE)–green fluorescent protein (GFP) reporter test system in Saccharomyces cerevisiae
They compared the activities in serum from 168 postmenopausal breast cancer patients and 125 age-matched controls.
There were no significant differences in estradiol levels between the two groups. But ERα and ERβ bioactivities were both increased in breast cancer cases compared with controls. Most of the increase was seen in ER-positive breast cancer cases only; there was a non-significant trend toward an increase in ERβ only for ER-negative cases compared with controls.
Logistic regression analysis showed that both ERα and ERβ bioactivities were significantly associated with breast cancer, and with ER-positive breast cancer in particular after adjusting for age and the bioactivity of the other receptor.
Women with ERα and ERβ bioactivities in the highest quintile of controls had a 7.6-fold risk for all breast cancer compared with women in the lowest quintiles, and a 10.1-fold risk for ER-positive disease.
This study, published in the British Journal of Cancer, is the first description of “a yeast-based serum bioactivity assay to predict the presence of breast cancer.”
The authors suggest that not only could this method be useful to predict breast cancer, but it could also “allow monitoring of preventive and therapeutic hormonal therapies.”
They add: “The use of serum ERα and ERβ bioactivity assays as clinical tools in the management of breast cancer warrants further research.”
By Catherine Nieman Sims