BackgroundThe role of estrogen receptor beta (ER-β) in breast cancer (BC) remains unclear. Some studies have suggested that ER-β may oppose the actions of estrogen receptor alpha (ER-α), and clinical evidence has indicated that the loss of ER-β expression is associated with a poor prognosis and resistance to endocrine therapy. The objective of the present study was to determine the role of ER-β and the ER-α/ER-β ratio in predicting the response to endocrine therapy and whether different regimens have any effect on ER-β expression levels.MethodsNinety postmenopausal patients with primary BC were recruited for a short-term double-blinded randomized prospective controlled study. To determine tumor cell proliferation, we measured the expression of Ki67 in tumor biopsy samples taken before and after 26 days of treatment with anastrozole 1 mg/day (N = 25), tamoxifen 20 mg/day (N = 24) or placebo (N = 29) of 78 participants. The pre- and post-samples were placed in tissue microarray blocks and submitted for immunohistochemical assay. Biomarker statuses (ER-β, ER-α and Ki67) were obtained by comparing each immunohistochemical evaluation of the pre- and post-surgery samples using the semi-quantitative Allred’s method. Statistical analyses were performed using an ANOVA and Spearman’s correlation coefficient tests, with significance at p ≤ 0.05.ResultsThe frequency of ER-β expression did not change after treatment (p = 0.33). There were no significant changes in Ki67 levels in ER-β-negative cases (p = 0.45), but in the ER-β-positive cases, the anastrozole (p = 0.01) and tamoxifen groups (p = 0.04) presented a significant reduction in post-treatment Ki67 scores. There was a weak but positive correlation between the ER-α and ER-β expression levels. Only patients with an ER-α/ER-β expression ratio between 1 and 1.5 demonstrated significant differences in Ki67 levels after treatment with anastrozole (p = 0.005) and tamoxifen (p = 0.026).ConclusionsOur results provide additional data that indicate that the measurement of ER-β in BC patients may help predict tamoxifen and anastrozole responsiveness in the neoadjuvant setting. These effects of hormonal treatment appear to be dependent on the ratio of ER-α/ER-β expression.Trial registrationCurrent Controlled Trials ISRCTN89801719

Male breast cancer accounts for 1% of all breast cancer cases, and men tend to be diagnosed at an older age than women (mean age is about 67 years). Several risk factors have been identified, such as genetic and hormonal abnormalities.The present study reported the case of a 25-year-old man who was diagnosed with an advanced invasive ductal carcinoma; however, he did not have any important risk factors.Even though more data is emerging about this disease, more efforts to understand risk factors, treatment options and survival benefits are needed. In this case, we discussed the risk factors as well as the impaired fertility associated with breast cancer therapies.