Combined profile of the tandem repeats CAG, TA and CA of the androgen and estrogen receptor genes in breast cancer

Purpose Case–control studies have reported inconsistent results concerning the association between polymorphisms in the androgen and estrogen receptor (ER) genes and breast cancer. While several studies investigated the association between the androgen receptor (AR) gene, CAG repeat and breast cancer, for the CA and TA repeats in the ER genes there are considerably fewer studies (one for CA and none for TA).Methods We have investigated the potential link between three tandem repeats (CAG, TA, and CA) in the AR, ERs α and β genes, respectively, and breast cancer. DNA was isolated from 153 invasive breast tumors and 318 controls, and the three tandem repeats were sized by polyacrylamide electrophoresis. Number of repeats in each allele and the total repeats of both alleles were taken as variables for classification into dichotomous groups using the median of each variable in the control group as cut-off point. Relationship between polymorphic tandem repeats and breast cancer was assessed by multivariate logistic regression models.Results Three variables combined, longer CAGsum (≥28), shorter TA (<23) and CA (<23) repeats could constitute a possible genetic profile associated with breast cancer.Conclusions Our results confirm previous reports regarding an association between longer CAG repeats and breast cancer. In addition to that, we found that the combination of long CAG, short TA and CA repeats are strongly associated with breast cancer.This paper was initially submitted with an additional co-author who withdrew the co-authorship during the review process. All listed authors have now signed that they agree with the content of the current paper.     

Estrogen receptor beta in breast cancer

Estrogen is essential for growth and development of the mammary glands and has been associated with the promotion and growth of breast cancer and in line with this, most human breast cancers are initially estrogen-dependent and undergo regression when deprived of their supporting hormone. Estrogen exerts many of its effects via two nuclear estrogen receptors (ERs), ERα and ERβ. The discovery of a second ER, ERβ, demanded a full re-evaluation of estrogen action in all target tissues and different estrogen associated diseases, including human breast cancer. However, despite over 15 years of research, the exact role, if any, of ERβ in human breast cancer remains elusive. The main challenges now are to develop highly selective anti-ERβ antibodies that are applied to large well characterized human breast cancer samples to validate their diagnostic potential and to explore ERβ-selective agonists in animal models of breast cancer to validate their therapeutic potential.     

A,B, H,and Lewis-a and Lewis-b blood group antigens in human breast cancer: Correlation with steroid hormone receptor and disease status

Estrogen (ER) and progesterone (PR) hormone receptor status and levels were correlated with blood group antigen (A, B, H, Lewis-a and Lewis-b) expression in 48 cases of human breast cancer. Reduced expression of all the blood group antigens was observed with statistically significant reductions for H, Lewis-a and Lewis-b (P<0.05). The proportions of ER- and PR-positive breast cancers staining for Lewis-b were greater than in hormone-receptor-negative cancers but the differences were not significant. The loss of Lewis-b antigen in breast cancer increased with tumor grade but did not correlate with axillary lymph node metastases. Loss of Lewis-b antigen is probably not a predictor of local recurrence and survival in the short period of observation. We conclude that the loss of H, Lewis-a and especially, Lewis-b in breast cancer reflects the invasiveness of breast cancer and that Lewis-a and b expression is probably only marginally and not significantly affected by steroid hormone receptor status and levels.     

Role of sex steroid receptors in pathobiology of hepatocellular carcinoma

The striking gender disparity observed in the incidence of hepatocellutar carcinoma （HCC） suggests an important role of sex hormones in HCC pathogenesis. Though the studies began as early as in 1980s, the precise role of sex hormones and the significance of their receptors in HCC still remain poorly understood and perhaps contribute to current controversies about the potential use of hormonal therapy in HCC. A comprehensive review of the existing literature revealed several shortcomings associated with the studies on estrogen receptor （ER） and androgen receptor （AR） in normal liver and HCC. These shortcomings include the use of less sensitive receptor ligand binding assays and immunohistochemistry studies for ERα alone until 1996 when ERβ isoform was identified. The animal models of HCC utilized for studies were primarily based on chemical-induced hepatocarcinogenesis with less similarity to virus-induced HCC pathogenesis. However, recent in vitro studies in hepatoma cells provide newer insights for hormonal regulation of key cellular processes including interaction of ER and AR with viral proteins. In light of the above facts, there is an urgent need for a detailed investigation of sex hormones and their receptors in normal liver and HCC. In this review, we systematically present the information currently available on androgens, estrogens and their receptors in normal liver and HCC obtained from in vitro, in vivo experimental models and clinical studies. This information will direct future basic and clinical research to bridge the gap in knowledge to explore the therapeutic potential of hormonal therapy in HCC.     

Estrogen receptor status and adjuvant polychemotherapy or antiestrogen therapy in patients with high-risk breast cancer

Summary This pilot study includes 115 consecutive patients admitted in the period from 1978 to 1981. Patients eligible for this study were at high risk according to the TNM classification with stages pT1-pT3 and pN+, MO. Primary therapy included modified radical mastectomy and axillary-node clearance, one or more ipsilateral nodes being involved in routine histology. All tumors were assayed for estrogen and progesterone receptors. According to the result of the estrogen receptor assay, estrogen-receptor-positive patients were treated with Tamoxifen 30 mg/day for a period of 2 years. Estrogen-receptor-negative patients were treated with cytoxan, methotrexate, and 5-fluorouracil or adriblastin, cytoxan. After a median observation time of 36 months, overall there have been 31 recurrences: 9=17.3% in the estrogen-receptor-positive group and 22=34.9% in the estrogen-receptor-negative group. The analysis of different subgroups showed no significant differences, either in relation to axillary lymph-node status or in relation to menopausal status in the endocrine-treated compared with the polychemotherapy group. This result suggests, especially in the subgroup of patients with involvement of one to three axillary nodes, that estrogen-receptor-positive and estrogen-receptor-negative patients should be considered as separate groups when adjuvant therapy is indicated. Possibly hormone-receptor-positive patients may benefit from endocrine therapy and do not need polychemotherapy.     

Correlation study between the polymorphism of repetitive sequence in gene CAG of androgen receptor and the occurrence and progression of prostate cancer

Objective:To explore the relation between the polymorphism of repetitive sequence in gene CAG of androgen receptor(AR)and the susceptibility and clinical stages as well as pathological grading of prostate cancer among Han population.Method:Sixty-eight cases with prostate cancer hospitalized in Urinary Surgery Department from Feb.2010 to Feb.2012 and 60 healthy cases were chosen as research subjects.Methods of PCR and direct sequencing were adopted to detect DNA sequence of AR gene and the length of repetitive sequence in CAG.Results:The lengths of repetitive sequence in CAG of patients with prostate cancer and healthy people were(22.3±4.6)and(23.0±4.9),respectively showing no statistical significance.Comparing length(repetitive sequence of CAG)22,those with that22 suffer a remarkably higher risk of prostate cancer(P0.05).The number of repetitive sequence in CAG of patients at clinical stage C-D was less than that of patients at stage B,and the number of repetitive sequence in CAG of patients with poorly differentiated prostate cancer was also less than that of patients with moderately and highly differentiated prostate cancer.But there was no statistical significance int the difference(P0.05);the proportion of patients with length22 at clinical stage C-D was much larger than that of patients at clinical stage B(P0.05),and as the aggravation of pathological grading,the proportion of patients with the length22 was also remarkably increased and there was significant difference between patients with highly differentiated prostate cancer and those with poorly differentiated prostate cancer(P0.05).Conclusions:There is correlation between the occurrence and development of prostate cancer in Han population and the polymorphism of repetitive sequence in gene CAG of androgen receptor.The less the number of repetitive sequence in CAG is,the higher the risk of prostate cancer will be and the more severe the clinical stage and pathological grading will be.     

Synthesis and post-translational modification of the androgen receptor in LNCaP cells

Androgen receptor synthesis and modification were studied in the human LNCaP cell line. Immunoblotting with a specific polyclonal antibody showed that the androgen receptor migrated as a closely spaced 110–112 kDa doublet on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels. Most of the receptor protein is present in the higher molecular mass form. Pulse labelling experiments with [³⁵S]methionine showed that the androgen receptor is synthesized as a single 110 kDa protein which is rapidly converted to a 112 kDa protein. Alkaline phosphatase treatment of cytosols from [³⁵S]methionine pulse labelled cells caused a gradual elimination of the 112 kDa isoform with a concomitant increase of the 110 kDa isoform. This indicates that the observed 110 to 112 kDa upshift of the newly synthesized androgen receptor reflects receptor phosphorylation. Both isoforms can bind hormone and can undergo a hormone dependent transformation to a tight nuclear binding form, indicating that the 110 to 112 kDa conversion is not an obligatory step for hormone binding or receptor transformation.     

原发性肝癌雌二醇及其受体的表达及意义

目的通过检测肝癌组织雌二醇（E2）及其受体（ER）表达，探讨雌二醇及其受体与肝癌的关系和意义。方法应用组织芯片和免疫组化S-P法检测48例肝癌、30例乙型肝炎肝硬化组织E2和ER表达．以正常肝组织为对照组，分析E2和ER与肝癌的关系和意义。结果肝癌组、肝硬化组及对照组E2阳性率分别为62．5％、56．7％、10．0％，肝癌组和肝硬化组阳性率均较对照组明显增加（P〈0．01）．肝癌组与肝硬化组两者无显著性差异；肝癌组ER阳性率（43．8％）与肝硬化组ER阳性率（63．3％）相比无显著性差异，但均显著高于对照组（15．0％，P〈0．05）。结论肝癌及肝硬化存在E2、ER高表达。在肝硬化期就已存在E2、ER含量增多，在肝硬化向肝癌的转变过程中，E2、ER发挥重要的促进作用。E2、ER与肝癌的发生发展有密切关系。     

Progesterone receptors A and B and estrogen receptor alpha expression in normal breast tissue and fibroadenomas

Fibroadenomas are the most common benign breast tumors, occurring mainly in young women. Their responses to the hormonal environment are similar to those of normal breast tissue, which suggests that steroid receptors may play a role in tumor development. We evaluated the gene and protein expression of progesterone receptors A and B (PRA and PRB) and the protein expression of estrogen receptor α (ER-α) in fibroadenoma samples, comparing with adjacent normal breast tissue, from 11 premenopausal women. Progesterone and estradiol levels were determined. No alterations in the PRs gene and protein expression and the ER-α protein expression were observed between the follicular and luteal phases, in normal breast versus fibroadenomas. Protein levels of PRA and PRB were higher in fibroadenomas compared to normal breast tissue (P = 0.038 and P = 0.031), while the PRs mRNA levels were similar in both tissues (P = 0.721 and P = 0.139). There were no differences in ER-α protein expression between normal breast tissue and fibroadenomas (P = 0.508). The PRA:PRB ratio was similar in the tissues, and also showed a strong correlation in both (r = 0.964, P = 0.0001). Our data suggest a role of PRs in the growth and development of fibroadenomas, although without alterations of the PRA:PRB ratio in these tumors. The absence of alterations in ER-α protein levels could be a characteristic behavior of fibroadenomas, unlike breast cancer.     

Influence of tissue heterogeneity on the determination of steroid receptors in breast cancer

Summary Biochemical determination of hormone receptors in carcinomas is influenced by the potential heterogeneity of the tissue samples. In order to check this, samples of 16 breast cancers were divided into 6 segments. These segments were alternately examined for their ratio of tumor tissue to connective tissue (percentage of carcinoma) or for the content of estrogen and progesterone receptors. Only 3 of the tumors were homogeneous, and 9 of the heterogeneous tissues had hormone receptors. The segment with the maximum percentage of carcinoma was adjacent to that with the peak value of hormone receptors in all but 1 tissue. The same applied to the minima. The maximum and minimum values of estrogen and progesterone receptors were located within the same segment in all but one tissue sample. The results demonstrated that biochemical assay of hormone receptors is reliable. A reduction of the sample volume does not enhance the precision of the receptor assay, since it increases the possibility of a false negative result.     

Control of immunity and allergy by steroid hormones

Steroid hormones, especially glucocorticoids, androgens, and estrogens, have profound influence on immunity. Recent studies using cell-type specific steroid hormone receptor-deficient mice have revealed the precise roles of some of these hormones in the immune system. Glucocorticoids are known to have strong anti-inflammatory and immunosuppressive effects and pleiotropic effects on innate and adaptive immune responses. They suppress the production of inflammatory cytokines by macrophages and DCs and the production of IFN-γ by NK cells, thus inhibiting innate immunity. By contrast, glucocorticoids enhance the immune response by inducing the expression of IL-7R and CXCR4 in T cells and the accumulation of T cells in lymphoid organs in accordance with the diurnal change of the glucocorticoid concentration. Thus, glucocorticoids suppress innate immunity but enhance adaptive immunity. Androgens suppress the homeostasis and activation of ILC2s and the differentiation of Th2 and Th17 cells and enhance the suppressive function of Tregs, thereby alleviating allergic airway inflammation. Thus, these steroid hormones have pleiotropic functions in the immune system. Further investigations are awaited on the regulation of immunity and allergy by estrogens using cell-specific steroid hormone receptor-deficient mice.     

Polymorphisms in androgen and estrogen receptor genes: effects on male aging

Besides lifestyle and environmental factors, the life-long exposure to the endocrine milieu of gonadal steroids is a determining factor to gender specific features of aging. In contrast to women, men do not experience a sudden cessation of gonadal function comparable to menopause. However, cross-sectional and longitudinal population studies demonstrate that the hormones with anabolic actions (e.g. testosterone [T], growth hormone, insulin-like growth factor [IGF]-1, dehydroepiandrosterone) do decrease progressively with aging in healthy men, and chronic systemic illnesses accelerate this process. In addition, estrogen has recently been established to be essential for normal physiology of the male. The slow progressive decline of the hypothalamic-pituitary-gonadal (HPG) function is thought to be responsible for many common signs and symptoms of aging men, such as general weakness, sexual dysfunction, and increased fat mass. There is a large inter-individual variation in sex hormone levels cross-sectionally within given age groups as well as longitudinally with aging. A contributing factor to this variability are the numerous functionally significant polymorphisms that have been detected in the receptors for androgen and estrogen. In this review, we summarize the recent information on some common polymorphisms in androgen and estrogen receptor genes and their effect on gender specific and aging-related symptoms and diseases of men.     

Tandem CAG repeats of the androgen receptor gene and prostate cancer risk in black and white men

The most common malignancy in men worldwide is cancer of the prostate. Androgens play a direct role in normal and malignant growth of prostate cells via the androgen receptor (AR). This study analyzed the polymorphic CAG repeat sequence in exon 1 of the AR gene to determine if the number of repeats might be an indicator of prostate cancer risk or aggressive disease. DNA was extracted from blood samples of 20 black and 20 white men with well-documented prostate cancer and 40 healthy, controls (20 blacks and 20 whites). PCR amplifications was followed by gel electrophoresis and DNA sequencing. This region normally contains between 9 and 29 repeats. Patients and controls both had minor variations in the number of repeats, which ranged from 13 to 27 with 21 being the most frequent allele. Black controls and patients both had a mean of 20±3, repeats; in whites the mean was significantly lower in patients than controls (21±2 versus 23±2; p=0.004). Combined black and white patients also had a lower number than the combined group of controls (20±3 versus 22±3; p=0.02). Similarly, black and white patients with aggressive disease has a lower number than patients whose disease was more slowly progressive (19±2 versus 22±3; p=0.02). We conclude that the small differences in the number of CAG repeats in both black and white patients do not appear to be a strong indicator of risk or aggressive disease but that this size polymorphism may be one of many genetic and environmental risk factors involved in prostate cancer.     

Steroid receptor expression in the developing copulatory system of the green anole lizard (Anolis carolinensis)

In adulthood, the copulatory system in male green anole lizards is characterized by the presence of two hemipenes, each controlled by ipsilateral muscles. These structures are present in both sexes early in development, but prior to hatching regress completely in females. Embryonic treatment with steroid hormones alters the morphology of the copulatory system, suggesting active roles for both androgens and estrogens in sexual differentiation. To elucidate the timing and sites of steroid hormone action in the embryonic copulatory system, the distributions of androgen receptor (AR) and estrogen receptor-alpha (ERα) mRNA expression were examined. In situ hybridization was conducted on the rostral tail of anoles at three stages spanning differentiation of the copulatory structures: embryonic days (E) 13, 18, and 24 (hatching occurs at approximately E34). At E13, males expressed significantly higher levels of AR mRNA in both hemipenes and muscles than did females, while females at the same age tended to express higher levels of ERα mRNA in these structures. By E18, hemipenes and copulatory muscles were regressed in most females, and were not present in any females at E24. In males, no effect of age was detected on the expression of either AR or ERα. These data suggest that peripheral copulatory structures in the embryonic anole are direct targets for the actions of both androgens and estrogens in sexual differentiation, consistent with the idea that estradiol facilitates regression in females and androgen promotes survival in males. However, the issue of whether or not a critical period exists remains open.     

The role of androgens and the androgen receptor in cycling endometrium

Androgens and the androgen receptor (AR) are not only required for male reproductive function, they are also essential for female reproductive physiology. Widely expressed in female reproductive tissues, AR levels fluctuate in a regulated manner in the cycling endometrium. Female androgen production depends on the adrenal glands and expression of key enzymes in the endometrium that facilitate local androgen biosynthesis and conversion. Moreover, levels of circulating androgens, in women of reproductive age, fluctuate in a cycle-dependent manner and a mid-cycle peak is associated with conception. AR and androgen signalling have a decisive role in the differentiation of human endometrial stromal cells into decidual cells. Compelling evidence for androgen signalling in the regulation of endometrial function pertaining to implantation and pregnancy is provided by epidemiological studies demonstrating a strong association between polycystic ovary syndrome, premature ovarian failure or advanced maternal age and adverse pregnancy outcome. Thus, androgen signalling is an essential component of normal endometrial physiology and its perturbation is associated with reproductive failure.     

Biological profile of oestrogen receptor positive primary breast cancers in the elderly and response to primary endocrine therapy

Aromatase inhibitors have been shown to be superior to Tamoxifen in several settings. It is unclear whether this superiority extends to their use as primary endocrine therapy in elderly patients with early operable primary breast cancer. Biological characteristics of the tumours may aid in selecting the most suitable agent.Primary endocrine therapy with Anastrozole in 64 women >70 years with oestrogen receptor α-positive (ERα+) breast cancer was compared to that in 84 treated with Tamoxifen during the same period. Biomarkers were assessed by immunohistochemistry on diagnostic core biopsies.There was no significant difference between the two groups (Anastrozole vs Tamoxifen) in terms of clinical benefit rates at 6 months (97% vs 100%) or median progression free survival (16.5 vs 22.5 months). There were no withdrawals due to adverse events from Anastrozole, compared to four with Tamoxifen. 46%, 99%, 8% and 5% of all patients were positive for progesterone receptor, ERβ2, HER2 and EGFR, respectively, and 64% of patients had a moderate Ki-67 index. Positive HER2 status (18 vs 21 months, p = 0.003) and moderate Ki-67 index (17.5 vs 23 months, p = 0.042) were associated with significantly shorter progression free survival.Results thus far show that primary endocrine therapy with Anastrozole in elderly patients with early operable ERα+ breast cancer is similar to Tamoxifen in terms of efficacy, but appears to be associated with less adverse events leading to withdrawals. In this population, ERα+ breast cancer also appears to have a less aggressive biological profile favouring better hormone sensitivity.