The Relationship Between Prognosis And Expression Of ER-β In Breast Cancer Tissue

Objective TTo detect the expression of estrogen receptorβsubtype(ER-β)in breast cancer tissue, and to investigate the significance of the expression of ER-βin breast cancer and the relationship between ER-βand prognosis.Methods 115 patients with breast cancer after operation and patients'clinical data were collected from the First Affiliated Hospital of Henan University of Technology and TScience in January 2005~ June 2006. Wax block of breast cancer were collected for detect the expression of ER-β,T and 26 cases of breast adenosis and 13 cases of normal breast tissues as a research control. The IHC method was used to detect the expression of ER-βin breast cancer, breast adenosis and normal breast tissue. And the study analyzed the expression of ER-βin the three tissues and its significance. Furthermore, the study analyzed the relationship between the expression of ER-βand other clinical pathological factors and its significance. A retrospective cohort study was devized to ivestigate prognosis of breast cancer patient. The study followed-up the breast cancer patients and survival data was collected continuously. Using the Kaplan-Meier method estimated the OS, DFS and survival curves plot of different groups and the Log-rank test or Cox-Mantel test tested the survival curves. Univariate cox regression model was used to evaluate the value of ER-βand other clinicopathological factors over the prognosis of breast cancer. Multivariate cox regression model, furthermore, was used to investigate whether ER-βand other clinicopathologic factors were independent prognostic factors in breast cancer patients.Results The rate of ER-βpositive was 70.43%, 96.15%, 100% respectively in breast cancer, breast adenosis and normal breast tissue, in which there existed difference statistically (x~2=12.163, P=0.003). There were not correlation between the expression of ER-βand patient's age, menstrual status, tumor size, axillary lymph node metastasis, pathological type, PR and C-erbB2. The expression of ER-βwas correlated with clinical stage (P=0.004) and histological grade (P=0.013) and had correlation positively with ER-α(r=0.295, P=0.040). 106 cases had been followed-up while 9 cases lost, and the rate of lost was 7.8%. The longest follow-up was 61 months, the shortest 43 months, and the mean follow-up time was 53±5 months. 35 patients were died of breast cancer. 3- and 5-years OS rate were 73.58%, 64.96% respectively and 3- and 5-years DFS rates were 72.64%, 56.88% respectively. Survival analysis showed 3- and 5-years OS and DFS in ER-βpositive group were 80.82%, 74.53%, 80.82%, 62.37% respectively while ER-βnegative group were 57.58%, 45.25%, 54.55%, 45.08%, and there existed difference statistically between the two groups(P<0.01). Sub-groups stratified analysis showed the 5-years OS of the patients of more than 50-years old, pre- and post-menopausal, tumor size of 2.1~5.0cm, histological gradeⅡ, invasive ductal carcinoma in ER-βpositive group much higher than subgroups in ER-βnegative, and there was difference statistically(P<0.05). Univariate analysis showed ER-β, tumor size, clinical stage, axillary lymph node metastases were prognostic factor of breast cancer. Multivariate analysis showed age, clinical stage, axillary lymph node metastasis and tumor size were independent prognostic factors in breast cancer. ER-βwas not an independent prognostic factor in breast cancer.Conclusions The rate of ER-βpositive in breast cancer is lower than that of breast adenosis and normal breast tissue, which suggests the occurrence of breast cancer may be related to the deficiency of ER-β. The expression of ER-βis correlated with clinical stage and histological grade, which indicates a better prognosis with expression of ER-β. ER-βis positively correlated ER-α, which suggests the patients of ER-βpositive may have a better response to treatment with TAM. Survival analysis show there are higher OS and DFS in the patients of ER-βpositive than ER-βnegative, which suggest ER-βis a good prognostic indicator of breast cancer. Univariate analysis too shows ER-βhas value in evaluating prognosis of breast cancer. Multivariate analysis shows ER-βwas not an independent prognostic factor. The study speculates that only detecting the expression of ER-βstill can not determine the prognosis of the patients. However, if combining other prognostic factors may still have some value.