The Expression Of ERα In The Thymic Epithelial Tumors And The Clinical Significance

Background& Objective:The thymic epithelial tumor derived from the epithelial cell is the most common anterior mediastinum of adult,with diverse biological and morphological characters,the prognosis of the tumor varies widely.The estrogen hormoneabelongs to the nuclear steroid hormone receptor Family ligand-dependent transcription of trans-regulatory proteins, three major functional domains are the N-terminal region, DNA binding domain and the C terminal region. As is known to all, the estrogen receptor awas found expressed in sex-hormone-dependent organ tumors such as breast cancer and endometrial cancer, the expression of the estrogen receptor a was observed in non sex-hormone-dependent organ tumors such as esophageal cancer,lung cancer.however,there are few studies about the estrogen hormoneain the thymic epithelial tumor. In this study, we perform immunohistochemistry to study the expression of estrogen receptor a in thymic epithelial tumor and its clinical significance.Method:All 71 TET tissues conformed by pathology were obtained the patients in Provincial Affiliated to Shandong University,16 thymic tissues from congenital heart disease were taken as controlled group.All the 87 specimens were examined by immunohistochemistry to detect the expression of ERaprotein.All the statistic analyses were performed with spss 17.0 statistical software.According to the clinical and pathological factors,the difference of ERaprotein expression was compared by X2 test. Kaplan-Meier method was performed to calculate the survival rate. Log-rank test was performed to compare the survival difference between the patients with and without ERαprotein positive expression.Cox regression multivariate analysis was performed to determine independent prognosis factors.Results:Of all the 71 TET specimens, ERαprotein was positive expression in 40(56.3%)specimens,while the ERαpositive expression rate in normal thymic tissues was 18.75%(3/16); the difference of ERαprotein between them was statistically significant(P<0.05). the ERαpositive expression rate in thymic carcinoma tissues was 80%(12/15),while ERαprotein positive expression rate in thymoma was 50%(28/56); their difference was statistically signifiant(P<0.05).The positive expression of ERαprotein in thymoma patients whose tumor diameter≤6cm were higher than those >6cm(P<0.05).Of 56 thymoma specimens,the ERαprotein positive expression rate in A+AB type was higer than that in B1+B2+B3 type(P<0.05)and the ERαprotein positive expression rate inⅠ+Ⅱstage was higer than that inⅢ+Ⅳstage(P<0.05).No significant correlations to age,gender,myasthenia,clinical stage of thymoma were demonstrated for ERαprotein positive expression. The WHO classification of TET is closely related to the Masaoka stage(P<0.05). the WHO type of thymomas is closely related to the complication of myasthenia gravis(P<0.05),especially B2 type(66.7%).The overall 5-year survival rate in 56 thymoma patients was 76.8%,the 5-year survival rate in patients with ERαprotein positive expression was higher than those without ERαprotein positive expression(82.1% vs 67.9%),their difference was statistically significant by Log-rank test(P=0.021<0.05).The overall 5-year survival rate in 15 thymic carcinoma patients was 26.7%, the 5-year survival rate in patients with ERαprotein positive expression was lower than those without ERαprotein positive expression(25% vs 33.3%),their difference was not statistically significant by Log-rank test(P=0.511>0.05).The results of Cox regression multivariate analysis conformed that Masaoka stage,WHO type and ERαprotein positive expression was independent prognosis factor.Conclusions:The ERαprotein expression in TET tissues was higher than that in normal thymic tissues,the ERαprotein expression in thymic carcinoma was higher than that in thymoma tissues and the ERαprotein expression in thymoma was found to be associated with tumor diameter and histopathological type.The WHO classification of TET is closely related to the Masaoka stage.the B type of thymomas is closely related to the complication of myasthenia gravis,especially B2 type.The results of Cox regression multivariate analysis conformed that Masaoka stage,WHO type and ERαprotein positive expression was independent prognosis factor.Our findings suggest ERαis a possible prognosis factor in thymoma.