Normal Breast Tissues And Expressions Of Nuclear Estrogen Receptors α And β In Fibroadenoma

Background and ObjectivesThe incidence of breast tumor is high in females, and the fibroadenoma is the mostcommon in benign tumors (approximately75%). Glandular epithelium and stromalcomponents are essential parts that pathological changes in fibroadenomas of the breastoccur, which can mainly appear as dysplastic glandular epithelial cells and stromalcomponents, but dysplastic stromal components generally. Fibroadenomas occur mostoften in age from20to30, but rarely in premenstrual and postmenopausal women.Fibroadenomas are estrogen-dependent, whose onset and development are associated withestrogen stimulation. Estrogen plays an important regulatory role in the growth anddevelopment of breast tissues, which is mainly mediated by nuclear estrogen receptors(ERs). It is mostly accepted that the onset and development of fibroadenoma are believedto be linked with abnormities of the quality and quantity of ERs although its etiology andpathogenesis are still unknown so far. Since1960s ERs were found and proposed on trialsby Mueller et al. and the ERα was replicated in1986, followed by ERβ found in the cDNAlibrary of rat prostate cell ten years later, the people made constant progress in studyingERs and had deeper understanding of distributions, functions and interactions of theirsubtypes in human body. Present studies at home and abroad reveal that both ERα and ERβare of ligand-activated transcriptional activation but both of them are found differences instructural feature, tissue distribution and signal transduction, so are those having differentligands and affinities with ligands. So far, there are many studies on the effects of ERs onboth normal breast tissues and onsets of breast cancer at home and abroad but less on theireffects in fibroadenoma. Therefore, this paper is mainly to study the expression levels anddistributions of ERα and ERβ in normal breast tissues and fibroadenomas in order todiscuss roles of ERs in the onset and development of fibroadenoma of breast, laying afoundation for further studies in the future. Materials and MethodsSpecimens collected in the trial were breast lumps from patients undergonelumpectomy in the General Surgery Department of the Laiwu City People’s Hospital fromApril to November2012, which were later confirmed as fibroadenomas of breast bypathological paraffin sections,20cases in total, unilaterally. All patients werenon-menopausal women, aged from17to40, with an average age of32.8. Specimens were2to3cm in diameter; no any treatment was performed within2months before surgerywithout other diseases. With normal breast tissue as control, there were20specimens inthis trial, which were obtained from corresponding surroundings of fibroadenomas of thebreast and were confirmed by pathology. After each specimen was fixed, embedded andsectioned, expressions of both ERα and ERβ in the specimen were detected by SPimmunohistochemistry. A statistical analysis was made on results of expressions of ERαand ERβ by chi-square test.Results1. Both ERα and ERβ expressed in normal breast tissues and fibroadenomas; ERαexpressed in glandular and ductal epithelial cells of both tissues, mostly in the nuclei butnot in stromal and myoepithelial cells. ERβ widely expressed in glandular epithelial,endothelial, stromal, myoepithelial cells and lymphocytes, mostly in nuclei andoccasionally in the cytoplasm.2. Compared with normal breast tissue, expression of ERα significantly increased infibroadenoma of the breast (P<0.05).3. Compared with normal breast tissue, expression of ERβ significantly reduced infibroadenoma of the breast (P<0.01).Conclusions1. Both ERα and ERβ express in normal breast tissues and fibroadenomas, and bothER subtypes regulate each tissue together.2. In normal breast tissues and fibroadenomas, ERα expresses in both glandular andductal epithelial cells, mostly in the nuclei but not in stromal and myoepithelial cells. ERβwidely expresses in glandular epithelial, endothelial, stromal, myoepithelial cells andlymphocytes, mostly in nuclei and occasionally in cytoplasm.3. Compared with normal breast tissue, in fibroadenoma of breast, expression of ERαsignificantly increases while that of ERβ significantly reduces; positive expression of ERαis significantly higher in fibroadenoma of breast than in normal breast tissue, whereas thatof ERβ significantly reduces, which may be the cause of the hyperplasia of glandular epithelial and fiber compositions of fibroadenoma.