Androgen receptor expresion in breast cancer: relationship with clinicopathological characteristics of the tumors, prognosis, and expression of metalloproteases and their inhibitors

Therapeutic resistance to anti-oestrogen therapy in breast cancer

The hormone receptor oestrogen receptor-α (ER) orchestrates physiological mammary gland development, breast carcinogenesis and the progression of breast tumours into lethal, treatment-refractory systemic disease. Selective antagonism of ER signalling has been one of the most successful therapeutic approaches in oncology, benefiting patients as both a cancer preventative measure and a cancer treatment strategy. However, resistance to anti-oestrogen therapy is a major clinical challenge. Over the past decade, we have gained an understanding of how breast cancers evolve under the pressure of anti-oestrogen therapy. This is best depicted by the case of oestrogen-independent mutations in the gene encoding ER (ESR1), which are virtually absent in primary breast cancer but highly prevalent (20-40%) in anti-oestrogen-treated metastatic disease. These and other findings highlight the 'evolvability' of ER+ breast cancer and the need to understand molecular processes by which this evolution occurs. Recent development and approval of next-generation ER antagonists to target ESR1-mutant breast cancer underscores the clinical importance of this evolvability and sets a new paradigm for the treatment of ER+ breast cancers.

The inhibition of steroid hormones determines the fate of IPC-366 tumor cells, highlighting the crucial role of androgen production in tumor processes

Inflammatory mammary cancer (IMC) is a disease that affects female dogs. It is characterized by poor treatment options and no efficient targets. However, anti-androgenic and anti-estrogenic therapies could be effective because IMC has a great endocrine influence, affecting tumor progression. IPC-366 is a triple negative IMC cell line that has been postulated as a useful model to study this disease. Therefore, the aim of this study was to inhibit steroid hormones production at different points of the steroid pathway in order to determine its effect in cell viability and migration in vitro and tumor growth in vivo. For this purpose, Dutasteride (anti-5αReductase), Anastrozole (anti-aromatase) and ASP9521 (anti-17βHSD) and their combinations have been used. Results revealed that this cell line is positive to estrogen receptor β (ERβ) and androgen receptor (AR) and endocrine therapies reduce cell viability. Our results enforced the hypothesis that estrogens promote cell viability and migration in vitro due to the function of E1SO4 as an estrogen reservoir for E2 production that promotes the IMC cells proliferation. Also, an increase in androgen secretion was associated with a reduction in cell viability. Finally, in vivo assays showed large tumor reduction. Hormone assays determined that high estrogen levels and the reduction of androgen levels promote tumor growth in Balb/SCID IMC mice. In conclusion, estrogen levels reduction may be associated with a good prognosis. Also, activation of AR by increasing androgen production could result in effective therapy for IMC because their anti-proliferative effect.

Assessment of the Androgen Receptor in Older Women with Primary Breast Cancer: Association with a Panel of Biomarkers and Breast Cancer Specific Survival

INTRODUCTION

Breast cancer in older women tends to have more favourable biology, compared to younger women. Androgen receptor (AR) is significant for breast tumour carcinogenesis; however, the role of AR in older women has not been fully explored.

METHODS

Surgical specimens were obtained from an existing series of 1758 older women (≥ 70 years) with primary breast cancer, treated in a single institution with long-term (≥ 37 years) follow-up. As part of previous work, it was possible to construct good quality tissue microarrays (TMAs) in 575 surgical specimens and a panel of 24 biomarkers was measured by immunohistochemistry (IHC) in these TMAs. AR positivity was assessed by IHC and defined as H-score ≥ 40. The relationship between AR in this cohort was compared to an equivalent group of younger women (< 70 years, n = 1708); the panel of 24 biomarkers and breast cancer specific survival (BCSS) in the older cohort.

RESULTS

AR was assessed in 509 samples. Overall, 59% of the older women cohort had positive expression of AR, compared to 63% in the younger cohort. AR positivity (regardless of age) was associated with smaller size of tumour, lower grade of tumour, lower tubule formation, lower nuclear polymorphism and lower mitotic frequency. AR positivity was associated with positive expression of oestrogen receptor (ER), progesterone receptor (PR), breast cancer gene 1 (BRCA1), cytokeratin (CK) 7/8, CK18, CK19, B cell lymphoma (Bcl)2 and Mucin 1 (Muc1) expression. Conversely, AR-positive expression was associated with negative expression of human epidermal growth factor receptor 2 (HER2), Ki-67, CK5, CK17, epidermal growth factor receptor (EGFR), and CD44 expression. Older women with AR-positive tumours had better BCSS compared to AR-negative tumours (p = 0.009).

CONCLUSIONS

There was no difference in AR expression between older and younger women with breast cancer. AR has prognostic potential in terms of BCSS. Further work is needed to investigate AR as a therapeutic target.

Evaluation of predictive and prognostic value of androgen receptor expression in breast cancer subtypes treated with neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy is the standard treatment for local advanced breast cancer administered to shrink tumors and destroy undetected metastatic cells, thereby facilitating subsequent surgery. Previous studies have shown that AR may be used as a prognostic predictor in breast cancers, but its role in neoadjuvant therapy and the relationship with prognosis of different molecular subtypes of breast cancer need to be further explored.

METHODS

We retrospectively evaluated 1231 breast cancer patients with complete medical records at Tianjin Medical University Cancer Institute and Hospital who were treated with neoadjuvant chemotherapy between January 2018 to December 2021. All the patients were selected for prognostic analysis. The follow-up time ranged from 12 to 60 months. We first analyzed the AR expression in different subtypes of breast cancer and its correlation with clinicopathological features. Meanwhile, the association of AR expression and pCR of different breast cancer subtypes was investigated. Finally, the effect of AR status on the prognosis of different subtypes of breast cancer after neoadjuvant therapy was analyzed.

RESULTS

The positive rates of AR expression in HR + /HER2-, HR + /HER2 +, HR-/HER2 + and TNBC subtypes were 82.5%, 86.9%, 72.2% and 34.6%, respectively. Histological grade III (P = 0.014, OR = 1.862, 95% CI 1.137 to 2.562), ER positive expression (P = 0.002, OR = 0.381, 95% CI 0.102 to 0.754) and HER2 positive expression (P = 0.006, OR = 0.542, 95% CI 0.227 to 0.836) were independent related factors for AR positive expression. AR expression status was associated with pCR rate after neoadjuvant therapy only in subtype of TNBC. AR positive expression was independent protective factor for recurrence and metastasis in HR + /HER2- (P = 0.033, HR = 0.653, 95% CI 0.237 to 0.986) and HR + /HER2 + breast cancer (P = 0.012, HR = 0.803, 95% CI 0.167 to 0.959), but was independent risk factors for recurrence and metastasis in TNBC (P = 0.015, HR = 4.551, 95% CI 2.668 to 8.063). AR positive expression is not an independent predictor of HR-/HER2 + breast cancer.

CONCLUSIONS

AR expressed the lowest in TNBC, but it could be a potential marker for the prediction of pCR in neoadjuvant therapy. AR negative patients had a higher pCR rate. AR positive expression was an independent risk factor for pCR in TNBC after neoadjuvant therapy (P = 0.017, OR = 2.758, 95% CI 1.564 to 4.013). In HR + /HER2- subtype and in HR + /HER2 + subtype, the DFS rate in AR positive patients and AR negative patients was 96.2% vs 89.0% (P = 0.001, HR = 0.330, 95% CI 0.106 to 1.034) and was 96.0% vs 85.7% (P = 0.002, HR = 0.278, 95% CI 0.082 to 0.940), respectively. However, in HR-/HER2 + and TNBC subtypes, the DFS rate in AR positive patients and AR negative patients was 89.0% vs 95.9% (P = 0.102, HR = 3.211, 95% CI 1.117 to 9.224) and 75.0% vs 93.4% (P < 0.001, HR = 3.706, 95% CI 1.681 to 8.171), respectively. In HR + /HER2- and HR + /HER2 + breast cancer, AR positive patients had a better prognosis, however in TNBC, AR-positive patients have a poor prognosis.

Expression of hormone receptors is associated with specific immunological profiles of the breast cancer microenvironment

BACKGROUND

Elucidating the unique immunoregulatory mechanisms in breast cancer microenvironment may help develop new therapeutic strategies. Some studies have suggested that hormone receptors also have immune regulatory functions, but their mechanisms are not fully understood. In this study, we have comprehensively analyzed the relationship between the expressions of estrogen (ER), progesterone (PgR), and androgen receptors (AR), and the immunological profile in breast cancer.

METHODS

Using publicly available gene expression profile datasets, METABRIC and SCAN-B, the associations between the expressions of hormone receptors and the immune cell compositions in breast cancer tissue, estimated by CIBERSORTx algorithm, were analyzed. We histologically evaluated tumor-infiltrating lymphocytes (hTIL), PD-L1 (hPD-L1) expression, and the infiltration of 11 types of immune cells by flow cytometry (FCM) for 45 breast cancer tissue samples. The relationships between them and the expressions of ER, PgR, and AR of tumor tissues, evaluated immunohistochemically, were analyzed.

RESULTS

Expressions of ESR1, PGR, and AR were negatively correlated with overall immune composition. Expressions of ER and AR, but not that of PgR, were inversely associated with hTIL and hPD-L1 expression. FCM analysis showed that the expressions of ER and AR, but not that of PgR, were associated with decreased total leukocyte infiltration. Both CIBERSORTx and FCM analysis showed that ER expression was associated with reduced infiltration of macrophages and CD4+ T cells and that of AR with reduced macrophage infiltration.

CONCLUSION

Hormone receptor expression correlates with specific immunological profiles in the breast cancer microenvironment both at the gene and protein expression levels.

Role of Nivolumab in the Modulation of PD-1 and PD-L1 Expression in Papillary and Clear Cell Renal Carcinoma (RCC)

The expression and cellular mechanisms of programmed cell death-1 protein (PD-1) and its ligands (PD-L1 and PD-L2) in renal cancer cells are not well known. Here, we aimed to investigate the response of renal carcinoma subtypes to the immune checkpoint inhibitor nivolumab and its impact on related signaling pathways. All cell lines analyzed (clear cell (cc)RCC (Caki-1, RCC31) and papillary (p)RCC (ACHN, RCC30)) expressed PD-1 and both ccRCC cell lines, and RCC30 expressed PD-L1. Nivolumab treatment at increasing doses led to increased PD-1 levels in analyzed cells and resulted in aggressive behavior of pRCC but diminished this behavior in ccRCC. The analysis of PD-1/PD-L1-associated signaling pathways demonstrated increased AKT activity in Caki-1 and RCC30 cells but decreased activity in ACHN and RCC31 cells, while ribosomal protein S6 remained largely unchanged. Androgen receptors are related to RCC and were predominantly increased in RCC30 cells, which were the only cells that formed nivolumab-dependent spheroids. Finally, all cell lines exhibited a complex response to nivolumab treatment. Since the pRCC cells responded with increased tumorigenicity and PD-1/PD-L1 levels while ccRCC tumorigenicity was diminished, further studies are needed to improve nivolumab-based therapy for renal carcinoma subtypes, especially the identification of response-involved molecular pathways.

Biomarkers and translational research approaches in breast cancer—an update

Diagnosis and decision-making in the treatment of breast cancer patients is vastly dependent on the exploration of biomarkers. Estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 are long-standing biomarkers, which determine the breast cancer subtype. In current practice, gene expression analyses further define the molecular breast cancer subtype and give additional information on disease characteristics. Prognostic biomarkers provide information regarding recurrence risk and survival. Predictive biomarkers, such as programmed cell death ligand 1 expression, are tools for identifying patients who can benefit from specific therapy regimens in order to choose the best treatment option for the patient. While some biomarkers are affordable and readily available, others remain technically complex to access. Translational research builds the bridge from discovering novel biomarkers in preclinical studies to testing their application utility in the clinical setting. Integrating translational studies into clinical trials is therefore essential to find novel and reliable biomarkers for an optimal personalized treatment approach for patients with breast cancer.

Androgen receptor function and targeted therapeutics across breast cancer subtypes

Despite significant progress in breast cancer (BC) therapy, it is globally the most commonly diagnosed cancer and leads to the death of over 650,000 women annually. Androgen receptor (AR) is emerging as a potential new therapeutic target in BC. While the role of AR is well established in prostate cancer (PCa), its function in BC remains incompletely understood. Emerging data show that AR's role in BC is dependent on several factors including, but not limited to, disease subtype, tumour microenvironment, and levels of circulating oestrogens and androgens. While targeting AR in PCa is becoming increasingly effective, these advances have yet to make any significant impact on the care of BC patients. However, this approach is increasingly being evaluated in BC and it is clear that improvements in our understanding of AR's role in BC will increase the likelihood of success for AR-targeted therapies. This review summarizes our current understanding of the function of AR across BC subtypes. We highlight limitations in our current knowledge and demonstrate the importance of categorizing BC subtypes effectively, in relation to determining AR activity. Further, we describe the current state of the art regarding AR-targeted approaches for BC as monotherapy or in combination with radiotherapy.

Clinicopathological features and androgen receptor expression in triple negative breast cancer at Lagos, Nigeria

INTRODUCTION

Androgen receptor (AR) is one of the predominant nuclear hormone receptors in invasive breast cancer and can be explored as a biomarker of response for targeted anti-androgen therapy, especially in the setting of triple negative breast cancer (TNBC). Luminal AR is a distinct subtype amongst TNBC cases following gene expression studies. TNBC is higher in Africans (23%-82%) and African-Americans (29.8%) compared to Caucasian (10%-15%) breast cancer patients; however, there is a paucity of data on AR expression in this population. The aim of this study is to determine the expression of AR and the proportion of AR positive cancers in TNBCs at the Lagos University Teaching Hospital, Lagos, Nigeria.

METHODOLOGY

Out of 99 reviewed cases, 78 formalin fixed, paraffin embedded TNBC cases were assembled into a tissue microarray, stained and analysed for AR expression using immunohistochemistry.

RESULTS

The mean age of the TNBC patients was 49.3 years (range: 20-80 years). The histologic types in this study were invasive carcinoma (no special type) 75.4%; metaplastic carcinoma 21.4%; lobular carcinoma and mucinous carcinoma 1.6% each. Of 61 TNBC cases analysed, 37.7% were AR positive and 62.3% were AR negative, making the latter to become quadruple negative breast cancers. There was a significant association between age and AR expression (p = 0.02). In the subjects that expressed AR positivity, patients below 50 years accounted for 34.8% (8 of 23) while 65.2% (15 of 23) were above 50 years. There was no significant association between AR expression and histologic type or tumour grade.

CONCLUSION

Over a third of this Nigerian TNBC cohort study is AR+. This warrants further exploration of the predictive and prognostic significance of its expression amongst TNBC and the potential for targeted therapy, specifically androgen antagonists to improve the outcome of this disease with limited therapeutic options.

Androgen receptor splice variant-7 in breast cancer: clinical and pathologic correlations

Androgen receptor (AR) inhibitor therapy is a developing treatment for AR-positive breast cancer (BC) with ongoing clinical trials. AR splice variant-7 (AR-V7) is a truncated variant of AR that leads to AR inhibitor therapy resistance in prostate cancer; recent studies have identified AR-V7 in BC and theorized that AR-V7 can have a similar impact. This study assessed the prevalence and clinicopathologic features associated with AR-V7 in a large BC cohort. BC samples were evaluated by MSK-Fusion targeted RNAseq for AR-V7 detection and MSK-IMPACT targeted DNAseq, including triple-negative tumors with no driver alteration and estrogen receptor-positive/ESR1 wildtype tumors progressing on therapy. Among 196 primary and metastatic/recurrent cases (196 RNAseq, 194DNAseq), 9.7% (19/196) were AR-V7 positive and 90.3% (177/196) AR-V7 negative. All AR-V7 positive BC were AR-positive by immunohistochemistry (19/19). The prevalence of AR-V7 by receptor subtype (N = 189) was: 18% (12/67) in ER-/PgR-/HER2-negative BC, 3.7% (4/109) in ER-positive/HER2-negative BC, and 15.4% (2/13) in HER2-positive BC; AR-V7 was detected in one ER-positive/HER2-unknown BC. Apocrine morphology was observed in 42.1% (8/19) of AR-V7 positive BC and 3.4% (6/177) AR-V7 negative BC (P < 0.00001). Notably, AR-V7 was detected in 2 primary BC and 7 metastatic/recurrent BC patients with no prior endocrine therapy. We conclude that positive AR IHC and apocrine morphology are pathologic features that may indicate testing for AR-V7 is warranted in both primary and metastatic BC in the appropriate clinical context. The study findings further encourage the assessment of AR-V7 as a predictive biomarker for AR antagonist benefit in ongoing clinical BC trials.

Triple-negative Breast Cancer (TNBC) and Its Luminal Androgen Receptor (LAR) Subtype: A Clinicopathologic Review of Cases in a University Hospital in Northwestern Nigeria

Background

Breast cancer (BC) is a common malignancy; the most frequent in Nigeria. BC characteristically exhibits great biologic diversity. Amongst its variants, the triple-negative subtype is also characterized by heterogeneity (thus making it a study in diversity within diversity) and also by some unique clinicopathologic features including clinical aggressiveness, lack of response to current targeted therapies, and tendency to cluster amongst young premenopausal women especially in populations of women of African ancestry.

Aims

The objective of this study was to conduct a retrospective clinicopathologic survey of all breast carcinomas to profile the triple-negative breast cancers (TNBCs) amongst them and illustrate their immunohistochemical pattern of luminal androgen receptors (LARs) expression.

Patients and Methods

All the cases entered into the departmental records as breast carcinomas over the study period were extracted including patients' request cards, hematoxylin and eosin-stained slides, and paraffin-embedded tissue blocks of those diagnosed as triple-negative cancers. These were immunohistochemically stained using a monoclonal antibody for androgen receptor (AR). The whole data were analyzed and presented in tabular formats.

Results

A total of 660 breast carcinomas of which 89 (13.48%) cases were identified as TNBCs with a mean age of occurrence of 42.89 ± 11.88 years. Most TNBCs (95.5%) were carcinoma no special type and 61.8% had low or intermediate histologic grading. LAR expression was noted in 11.24% of the TNBCs.

Conclusion

Triple-negative cancer in this study shares some of the known characteristics but also portrays some divergence from the commonly described features.

FOXA1: A Pioneer of Nuclear Receptor Action in Breast Cancer

The pioneering function of FOXA1 establishes estrogen-responsive transcriptomes in luminal breast cancer. Dysregulated FOXA1 chromatin occupancy through focal amplification, mutation, or cofactor recruitment modulates estrogen receptor (ER) transcriptional programs and drives endocrine-resistant disease. However, ER is not the sole nuclear receptor (NR) expressed in breast cancers, nor is it the only NR for which FOXA1 serves as a licensing factor. Receptors for androgens, glucocorticoids, and progesterone are also found in the majority of breast cancers, and their functions are also impacted by FOXA1. These NRs interface with ER transcriptional programs and, depending on their activation level, can reprogram FOXA1-ER cistromes. Thus, NR interplay contributes to endocrine therapy response and resistance and may provide a vulnerability for future therapeutic benefit in patients. Herein, we review what is known regarding FOXA1 regulation of NR function in breast cancer in the context of cell identity, endocrine resistance, and NR crosstalk in breast cancer progression and treatment.

The importance of androgen receptors in breast cancer

Background and aim

Breast cancer (BC) is the most common malignancy among women worldwide, and one of the leading causes of cancer-related deaths in females. For the breast malignant tumors there are numerous targeted therapies, depending on the receptors expressed. Regulating the process of epithelial-mesenchyme transcription, the steroid nuclear receptors are important in invasion and progression of BC cells. Till now, it is known that androgen receptor (AR) is present in about 60-80% of BC cells but, unfortunately, there is no targeted therapy available yet.

Methods

We revised the recent literature that included the AR mechanism of action in patients diagnosed with breast cancer, the preclinical, retrospective and clinical studies and the aspects related to the prognosis of these patients, depending on the molecular subtype.

Results

A total of 12 articles were eligible for this review. AR positivity was assessed using immunohistochemistry. Herein, neither 1 nor 10% cut-points were robustly prognostic. AR was an independent prognostic marker of BC outcome, especially in triple negative BC group.

Conclusion

AR is a potential targeted pathway which can improve the prognostic of AR positive patients with BC. Further preclinical and clinical studies are necessary to clarify the mechanism of action and to establish the drugs which can be used, either alone or in combination.

Differential Expression of the Androgen Receptor, Splice Variants and Relaxin 2 in Renal Cancer

Background: The role of the androgen receptor (AR) in renal cell carcinoma (RCC) is unclear. We aimed to analyze the expression of AR and its splice variants (SVs) and their correlation with relaxin 2 (RLN2) and cytokines in RCC. Methods: We investigated the expression of RLN2 and AR variants in 25 clear cell RCC (ccRCC) and 9 papillary (pRCC) tumor tissues and the corresponding controls using quantitative PCR and serum RLN2, testosterone and cytokine levels in matched samples using ELISA and chemiluminescent immunometric assay, respectively. Results: ccRCC tissues but not pRCC tissues more frequently expressed AR and the SVs than did normal tissues. All pRCC samples expressed more AR than did ccRCC samples. The highest expression of all AR variants except AR-V12 was found in low-stage tumors, with dominant expression of AR-V7. In males in the ccRCC cohort, the expression of AR-FL, AR-V1 and AR-V3 was significantly correlated with that of RLN2. The secretion pattern of proinflammatory IL-6 was higher in ccRCC than in pRCC. Conclusions: The results highlight additional molecular differences between ccRCC and pRCC, suggesting the influence of external factors on the whole kidney or genetic predispositions to developing certain types of renal cancer, and may support further pathological analysis and studies of targeted hormone therapy.

From Conventional to Precision Therapy in Canine Mammary Cancer: A Comprehensive Review

Canine mammary tumors (CMTs) are the most common neoplasm in intact female dogs. Canine mammary cancer (CMC) represents 50% of CMTs, and besides surgery, which is the elective treatment, additional targeted and non-targeted therapies could offer benefits in terms of survival to these patients. Also, CMC is considered a good spontaneous intermediate animal model for the research of human breast cancer (HBC), and therefore, the study of new treatments for CMC is a promising field in comparative oncology. Dogs with CMC have a comparable disease, an intact immune system, and a much shorter life span, which allows the achievement of results in a relatively short time. Besides conventional chemotherapy, innovative therapies have a large niche of opportunities. In this article, a comprehensive review of the current research in adjuvant therapies for CMC is conducted to gather available information and evaluate the perspectives. Firstly, updates are provided on the clinical-pathological approach and the use of conventional therapies, to delve later into precision therapies against therapeutic targets such as hormone receptors, tyrosine kinase receptors, p53 tumor suppressor gene, cyclooxygenases, the signaling pathways involved in epithelial-mesenchymal transition, and immunotherapy in different approaches. A comparison of the different investigations on targeted therapies in HBC is also carried out. In the last years, the increasing number of basic research studies of new promising therapeutic agents on CMC cell lines and CMC mouse xenografts is outstanding. As the main conclusion of this review, the lack of effort to bring the in vitro studies into the field of applied clinical research emerges. There is a great need for well-planned large prospective randomized clinical trials in dogs with CMC to obtain valid results for both species, humans and dogs, on the use of new therapies. Following the One Health concept, human and veterinary oncology will have to join forces to take advantage of both the economic and technological resources that are invested in HBC research, together with the innumerable advantages of dogs with CMC as a spontaneous animal model.

Luteolin suppresses androgen receptor-positive triple-negative breast cancer cell proliferation and metastasis by epigenetic regulation of MMP9 expression via the AKT/mTOR signaling pathway

BACKGROUND

Triple-negative breast cancer (TNBC) represents up to 20% of all breast cancers. This cancer lacks the expression of the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. The current therapeutic strategy for patients with this subtype is the use of cytotoxic chemotherapy and surgery. Luteolin is a natural herbal flavonoid and a potential therapeutic candidate for multiple diseases. The use of a treatment that combines Chinese herbal medicine and western medicine is rising in Asia.

PURPOSE

The present study evaluates the effects and molecular mechanisms involved with luteolin treatment and evaluates whether this herb affects androgen receptor-positive breast cancer cell proliferation or metastasis.

STUDY DESIGN

In vitro evaluation of the effect of luteolin on androgen receptor-positive TNBC cell proliferation and metastasis METHODS: Cell viability analysis was used for the cytotoxicity test. Colony formation and Bromodeoxyuridine (BrdU) staining-based proliferation experiments were used for cell proliferation. Wound healing and transwell assays were used for in vitro migration/invasion. The RT-qPCR analysis was used for gene expression. Furthermore, ChIP-qPCR analysis was used for epigenetic modification of gene promoters.

RESULTS

Luteolin significantly inhibited the proliferation and metastasis of androgen receptor-positive TNBC. Furthermore, luteolin inactivated the AKT/mTOR signaling pathway and reversed the epithelial-mesenchymal transition (EMT). The combination of luteolin and inhibitors of AKT/mTOR synergistically repressed an androgen receptor-positive TNBC cell proliferation and metastasis. Luteolin also downregulated MMP9 expression by decreasing the levels of the AKT/mTOR promoting H3K27Ac and H3K56A on the MMP9 promoter region.

CONCLUSION

Our findings indicate that luteolin inhibited the proliferation and metastasis of androgen receptor-positive TNBC by regulating MMP9 expression through a reduction in the levels of AKT/mTOR-inducing H3K27Ac and H3K56Ac.

Serial [18F]-FDHT-PET to predict bicalutamide efficacy in patients with androgen receptor positive metastatic breast cancer

BACKGROUND

The androgen receptor (AR) is a potential target in metastatic breast cancer (MBC), and 16β-[¹⁸F]-fluoro-5α-dihydrotestosterone positron emission tomography ([¹⁸F]-FDHT-PET) can be used for noninvasive visualisation of AR. [¹⁸F]-FDHT uptake reduction during AR-targeting therapy reflects AR occupancy and might be predictive for treatment response. We assessed the feasibility of [¹⁸F]-FDHT-PET to detect changes in AR availability during bicalutamide treatment and correlated these changes with treatment response.

PATIENTS AND METHODS

Patients with AR + MBC, regardless of oestrogen receptor status, received an [¹⁸F]-FDHT-PET at baseline and after 4-6 weeks bicalutamide treatment. Baseline [¹⁸F]-FDHT uptake was expressed as maximum standardised uptake value. Percentage change in tracer uptake, corrected for background activity (SUV_cor), between baseline and follow-up PET scan (% reduction), was assessed per-patient and lesion. Clinical benefit was determined in accordance with Response Evaluation Criteria in Solid Tumours (RECIST) 1.1 or clinical evaluation (absence of disease progression for ≥24 weeks).

RESULTS

Baseline [¹⁸F]-FDHT-PET in 21 patients detected 341 of 515 lesions found with standard imaging and 21 new lesions. Follow-up [¹⁸F]-FDHT-PET was evaluable in 17 patients with 349 lesions, showing a decrease in median SUV_cor from 1.3 to 0.7 per-patient and lesion (P < 0.001). Median % reduction per-patient was -45% and per-lesion -39%. In patients with progressive disease (n = 11), median % reduction was -30% versus -53% for patients who showed clinical benefit (in accordance with RECIST (n = 3) or clinical evaluation (n = 3); P = 0.338).

CONCLUSION

In this feasibility study, a bicalutamide-induced reduction in [¹⁸F]-FDHT uptake could be detected by follow-up [¹⁸F]-FDHT-PET in patients with AR + MBC. However, this change could not predict bicalutamide response.

CLINICAL TRIAL INFORMATION

NCT02697032.

A Phase II Clinical Trial of Pembrolizumab and Enobosarm in Patients with Androgen Receptor-Positive Metastatic Triple-Negative Breast Cancer

LESSONS LEARNED

The combination of enobosarm and pembrolizumab was well tolerated and showed a modest clinical benefit rate of 25% at 16 weeks. Future trials investigating androgen receptor-targeted therapy in combination with immune checkpoint inhibitors are warranted.

BACKGROUND

Luminal androgen receptor is a distinct molecular subtype of triple-negative breast cancer (TNBC) defined by overexpression of androgen receptor (AR). AR-targeted therapy has shown modest activity in AR-positive (AR+) TNBC. Enobosarm (GTx-024) is a nonsteroidal selective androgen receptor modulator (SARM) that demonstrates preclinical and clinical activity in AR+ breast cancer. The current study was designed to explore the safety and efficacy of the combination of enobosarm and pembrolizumab in patients with AR+ metastatic TNBC (mTNBC).

METHODS

This study was an open-label phase II study for AR+ (≥10%, 1+ by immunohistochemistry [IHC]) mTNBC. Eligible patients received pembrolizumab 200 mg intravenous (IV) every 3 weeks and enobosarm 18 mg oral daily. The primary objective was to evaluate the safety of enobosarm plus pembrolizumab and determine the response rate. Peripheral blood, tumor biopsies, and stool samples were collected for correlative analysis.

RESULTS

The trial was stopped early because of the withdrawal of GTx-024 drug supply. Eighteen patients were enrolled, and 16 were evaluable for responses. Median age was 64 (range 36-81) years. The combination was well tolerated, with only a few grade 3 adverse events: one dry skin, one diarrhea, and one musculoskeletal ache. The responses were 1 of 16 (6%) complete response (CR), 1 of 16 (6%) partial response (PR), 2 of 16 (13%) stable disease (SD), and 12 of 16 (75%) progressive disease (PD). Response rate (RR) was 2 of 16 (13%). Clinical benefit rate (CBR) at 16 weeks was 4 of 16 (25%). Median follow-up was 24.9 months (95% confidence interval [CI], 17.5-30.9). Progression-free survival (PFS) was 2.6 months (95% CI, 1.9-3.1) and overall survival (OS) was 25.5 months (95% CI, 10.4-not reached [NR]).

CONCLUSION

The combination of enobosarm and pembrolizumab was well tolerated, with a modest clinical benefit rate of 25% at 16 weeks in heavily pretreated AR+ TNBC without preselected programmed death ligand-1 (PD-L1). Future clinical trials combining AR-targeted therapy with immune checkpoint inhibitor (ICI) for AR+ TNBC warrant investigation.

Androgen receptor expression in a Sri Lankan patient cohort with early breast carcinoma

BACKGROUND

Androgen receptor (AR) expression is emerging as a prognostic biomarker in breast carcinoma (BCa). The study aimed to determine the prevalence of AR expression by immunohistochemical analysis among a cohort of Sri Lankan women with early BCa and to evaluate its association with clinicopathological features including immunohistochemical molecular subtype and early survival.

METHOD

We studied the clinical and pathological features and immunohistochemical profile of 141 women undergoing primary surgery for early BCa, followed by standard adjuvant therapy. AR status was assessed by immunohistochemistry in all cases. Overall survival (OS) and disease-free survival (DFS) was determined. The relationship between AR expression and clinical and pathological parameters and immunohistochemical molecular subtype was analyzed using Student T test and chi-square tests. Cox regression analysis was used to analyze the prognostic impact of AR expression.

RESULTS

AR expression was seen in 40.8%(95%CI 33.10-49.07%) of the BCa study cohort. None of the clinical data studied showed a significant association with the AR status(p > 0.05). Ductal carcinoma in situ(p = 0.003), oestrogen receptor (ER) (p = 0.001) and progesterone receptor (PR) (p = 0.001) positivity and luminal IHC molecular subtype(p = 0.016) were significantly associated with AR-positive status. AR-negative status was significantly associated with tumour necrosis > 50%(p = 0.031), moderate to extensive lymphocytic infiltrate at the tumour margin(p = 0.025) and basal triple negative breast carcinoma(p = 0.016). The mean duration of patient follow-up was 46.70(95% CI 46.495-46.905) months (3.89 years). On univariate analysis, AR-positivity was associated with better OS among ER-positive tumours(p = 0.047), specifically in postmenopausal women (p = 0.030). In ER-negative tumours, AR positivity was associated with worse DFS (p = 0.036). On multivariate analysis, TNM stage and ER/AR status were predictive of survival. ER-positive/AR-positive (ER+/AR+) tumours demonstrated better OS than ER-positive/AR-negative (ER+/AR-) tumours(p = 0.015). ER-negative/AR-positive (ER-/AR+) tumours (p = 0.014) had a worse DFS than ER-negative/AR-negative (ER-/AR-) tumours.

CONCLUSIONS

AR prevalence obtained was low. AR positivity was associated with positivity for ER and PR. On multivariate analysis, apart from TNM stage only ER/AR status were predictive of OS and DFS, with concordant expression of ER/AR demonstrating a better, early survival.

Expression of metalloproteinases MMP-2 and MMP-9 is associated to the presence of androgen receptor in epithelial ovarian tumors

BACKGROUND

The current study evaluated the metalloproteinases MMP-2 and MMP-9 expression in epithelial cells and the surrounding stroma in ovarian tumors and the association of MMPs with the histological subtypes, the clinical stage and the presence of steroid hormone receptors. Tumor samples were obtained from 88 patients undergoing surgical cytoreduction of primary ovarian tumors in Instituto Nacional de Cancerología, from México City. The formalin fixed and paraffin embedded samples were processed in order to demonstrate the presence of androgen receptor,estrogen receptor alpha, progesterone receptor, MMP-2,MMP-9 and collagen IV by immunohistochemistry and/or immunofluorescence.

RESULTS

MMP-2 and MMP-9 were differentially expressed in the epithelium and the stroma of ovarian tumors associated to histological subtype, clinical stage and sexual steroid hormone receptor expression. Based on Cox proportional hazard regression model we demonstrated that MMP-2 located in the epithelium and the stroma are independent prognostic biomarkers for overall survival in epithelial ovarian tumors. Kaplan Meir analysis of the combination of AR (+) with MMP-2 (+) in epithelium and AR (+) with MMP-2 (-) in stroma displayed a significant reduction of survival.

CONCLUSIONS

The presence of MMP-2 in the stroma of the tumor was a protective factor while the presence of MMP-2 in the epithelium indicated an adverse prognosis. The presence of AR associated with MMP-2 in the tumor cells was a risk factor for overall survival in epithelial ovarian cancer.

Clinicopathological Relevance and Prognostic Value of Androgen Receptor in Mammary Paget's Disease with Underlying Invasive Ductal Carcinoma

INTRODUCTION

Mammary Paget's disease (MPD) is a rare cutaneous manifestation. Epidemiologically, more than half of the MPD patients concurrently have underlying invasive ductal carcinoma (MPD-IDC), and their prognosis remains poor despite multimodal treatments of breast cancer have markedly improved patients' survival. Accordingly, it is crucial to seek out novel therapeutic targets of MPD-IDC. As an emerging biological marker, the value of androgen receptor (AR) in MPD-IDC is inconsistent. Our objectives were to investigate the associations between AR and clinicopathological factors, and to explore its prognostic value in MPD-IDC.

METHODS

We retrospectively analyzed data from 103 MPD-IDC patients, and immunohistochemical staining was used to determine their AR statuses.

RESULTS

AR was expressed in 44 patients (42.7%), and AR expression was significantly correlated with body mass index (BMI) (p = 0.038) and axillary lymph node (ALN) status (p = 0.025). Kaplan-Meier curves showed that AR positivity was significantly associated with better overall survival (OS) in MPD-IDC patients (p = 0.019) and estrogen receptor-negative MPD-IDC patients (p = 0.039). Multivariate Cox regression analysis revealed that AR was not an independent prognostic indicator of disease-free survival (DFS) or OS in MPD-IDC patients (p = 0.395 and p = 0.073, respectively).

CONCLUSIONS

In contrast to AR-negative tumors, patients with AR-positive ones were more likely to have lower BMI, no ALN metastasis, and better OS. AR-targeted treatments for MPD-IDC may add to existing therapeutic approaches to improve their effectiveness.

Androgen Receptor Expression and Breast Cancer Survival: Results From the Nurses' Health Studies

BACKGROUND

Hormone receptor signaling is critical in the progression of breast cancers, although the role of the androgen receptor (AR) remains unclear, particularly for estrogen receptor (ER)-negative tumors. This study assessed AR protein expression as a prognostic marker for breast cancer mortality.

METHODS

This study included 4147 pre- and postmenopausal women with invasive breast cancer from the Nurses' Health Study (diagnosed 1976-2008) and Nurses' Health Study II (1989-2008) cohorts. AR protein expression was evaluated by immunohistochemistry and scored through pathologist review and as a digitally quantified continuous measure. Hazard ratios (HR) and 95% confidence intervals (CI) of breast cancer mortality were estimated from Cox proportional hazards models, adjusting for patient, tumor, and treatment covariates.

RESULTS

Over a median 16.5 years of follow-up, there were 806 deaths due to breast cancer. In the 7 years following diagnosis, AR expression was associated with a 27% reduction in breast cancer mortality overall (multivariable HR = 0.73, 95% CI = 0.58 to 0.91) a 47% reduction for ER+ cancers (HR = 0.53, 95% CI = 0.41 to 0.69), and a 62% increase for ER- cancers (HR = 1.62, 95% CI = 1.18 to 2.22) (P heterogeneity < .001). A log-linear association was observed between AR expression and breast cancer mortality among ER- cancers (HR = 1.14, 95% CI = 1.02 to 1.26 per each 10% increase in AR), although no log-linear association was observed among ER+ cancers.

CONCLUSIONS

AR expression was associated with improved prognosis in ER+ tumors and worse prognosis in ER- tumors in the first 5-10 years postdiagnosis. These findings support the continued evaluation of AR-targeted therapies for AR+/ER- breast cancers.

Androgen Receptor Expression and Its Correlation with Clinicopathological Parameters in Iranian Patients with Triple Negative Breast Cancer

BACKGROUND & OBJECTIVE

Our knowledge about correlation of androgen receptor expression and clinicopathological properties of triple-negative breast cancer (TNBC) patients is inadequate, particularly in the Iranian population. The main aim of the present study was to assess the AR expression in TNBC Iranian patients and evaluate its correlation with their clinicopathological parameters.

METHODS

Herein, 76 TNBC patients were evaluated for the AR expression by immunohistochemistry. The slides' staining intensity was investigated according to the average degree of nuclear staining and sub-classified into negative (0), weak (1), moderate (2), or strong (3). Subsequently, the positive cells percentage for each slide was assessed and sub-classified into <25% (1), 25-50% (2), 50-75% (3), and >75% (4). The aggregation of these two scores was used as the final score ranging from 0 to 7. While 4-7 scores were selected as positive, the others were included in the AR-negative expression group. Fisher's exact test was used to analyze the AR expression correlation with the clinicopathological parameters.

RESULTS

Positive immunoreactivity for AR was observed in 8 out of 76 (11%) specimens. No-correlation (P>0.05) was observed between the AR expression and grade, stage, lymph node status, and Ki-67 level. The AR-positive patients exhibited older age at the time of diagnosis (P=0.0339) and larger tumor size (P=0.0224) in comparison with the AR-negative patients. Low percentage of TNBC patients expressed AR and no significant correlation was observed between its expression and most of the clinicopathological parameters.

CONCLUSION

AR may not be a suitable biomarker and treatment target for the Iranian patients with TNBC.

Radiopharmaceuticals for Breast Cancer and Neuroendocrine Tumors: Two Examples of How Tissue Characterization May Influence the Choice of Therapy

Molecular medicine has gained clinical relevance for the detection and staging of oncological diseases, to guide therapy decision making and for therapy follow-up due to the availability of new highly sensitive hybrid imaging camera systems and the development of new tailored radiopharmaceuticals that target specific molecules. The knowledge of the expression of different receptors on the primary tumor and on metastases is important for both therapeutic and prognostic purposes and several approaches are available aiming to achieve personalized medicine in different oncological diseases. In this review, we describe the use of specific radiopharmaceuticals to image and predict therapy response in breast cancer and neuroendocrine tumors since they represent a paradigmatic example of the importance of tumoral characterization of hormonal receptors in order to plan a tailored treatment. The most attractive radiopharmaceuticals for breast cancer are 16α-[¹⁸F]-fluoro-17β-estradiol for PET assessment of the estrogen expression, radiolabeled monoclonal antibody trastuzumab to image the human epidermal growth factor receptor 2, but also the imaging of androgen receptors with [¹⁸F]-fluorodihydrotestosterone.

Androgen receptor and FOXA1 coexpression define a "luminal-AR" subtype of feline mammary carcinomas, spontaneous models of breast cancer

Background

Invasive mammary carcinomas that spontaneously develop in female cats are associated with high mortality, and resemble the most aggressive human breast cancers, especially triple-negative breast cancer (TNBC). Transcriptome studies showed that TNBCs are a heterogeneous group that includes a potentially hormone-dependent subtype named luminal-AR. Some authors proposed an immunohistochemical definition of the luminal-AR subtype, which is not only positive for Androgen Receptor (AR), but also either positive for the transcription factor Forkhead box A1 (FOXA1), or negative for basal markers. The objectives of this study were to describe AR and FOXA1 expressions in feline mammary carcinomas (FMCs), their prognostic value, and if their coexpression could define a “luminal-AR” subtype of triple-negative mammary carcinomas in cats.

Methods

In a previously described retrospective cohort of 180 female cats with FMCs, with a 2-year follow-up post-mastectomy, we assessed AR, FOXA1, ER, PR, Ki-67, HER2, and CK14 expressions by automated immunohistochemistry.

Results

Of the 180 FMCs, 57 (32%) were luminal; i.e., ER and/or PR positive, and 123 (68%) were triple-negative (ER–, PR– and HER2–) FMCs. AR overexpression (found in 33 cases/180, 18%) and FOXA1 index ≥1% (64/180, 36%) were associated with a longer disease-free interval, overall survival, and cancer-specific survival in cats with FMC. Analysis of AR, FOXA1 and CK14 coexpression in triple-negative FMCs showed that AR+ triple-negative FMCs were heterogeneous: there existed an AR+ FOXA1+ CK14– subgroup (n = 7) associated with a better cancer-specific survival by multivariate survival analysis (HR = 0.26, 95% CI: 0.07–0.89, p = 0.03) compared to AR+ FOXA1–CK14+ triple-negative FMCs (n = 46) (HR = 1.00), independently of the pathologic tumor size and pathologic nodal stage. The non-basal-like subtype of triple-negative FMCs that coexpresses AR and FOXA1 (the AR+ FOXA1+ CK14– subgroup) could represent the equivalent of the luminal-AR subgroup of human triple-negative breast cancer.

Conclusions

We identified an AR+ FOXA1+ CK14– subgroup of triple-negative FMCs that might correspond to the luminal-AR subgroup of human triple-negative breast cancers. Cats with FMC may be interesting spontaneous animal models to investigate new strategies targeting the androgen receptor, especially in the aggressive subtype of AR+ basal-like triple-negative mammary carcinomas with loss of FOXA1 expression (the AR+ FOXA1–CK14+ subgroup).

Synergistic action of folate intake and testosterone associated with breast cancer risk

The amount of irreparable DNA damage is a function of the rate of cell division, and the association between sex hormones and the risk of breast cancer has been explained by an increase in cell division. Folate intake insufficiency leads to disturbances in DNA replication and DNA repair. We hypothesized that folate intake insufficiency and high serum concentrations of sex hormones act synergistically on the risk of breast cancer. The aim of this study was to investigate the interaction between sex hormones (exposure of interest A) and dietary folate intake (exposure of interest B) on the risk of breast cancer. We included 342 breast cancer primary postmenopausal cases and 294 controls obtained from a large population-based case-control study. Multiple conditional logistic regression models were used for the analysis and interactions were tested. The joint effect of the lowest dietary folate intake (T1 < 259.40 mg/d) and the highest serum concentration of testosterone (T3 ≥ 0.410 on the risk of breast cancer was odds ratio = 9.18 (95% confidence interval 2.56-32.88) when compared to the lowest-risk category, namely, the group of women with the highest dietary folate intake (T3 > 381.29 mg/d) and the lowest serum concentration of testosterone (T1 ≤ 0.25 pg/mL). There were some indications that the estimated join effect was greater than the product of the estimated effects alone (P = .001). These findings have important public health implications with respect to reducing the risk of the most frequent cancer in women worldwide.

Androgen receptor expression and response to chemotherapy in breast cancer patients treated in the neoadjuvant TECHNO and PREPARE trial

Background

The androgen receptor (AR) is discussed as a prognostic and/or predictive marker in breast cancer patients.

Methods

AR mRNA expression was analysed by RT-qPCR in breast cancer patients treated in the neoadjuvant TECHNO (n  =  118, HER2-positive) and PREPARE trial (n  =  321, HER2-positive and -negative). In addition, mRNA expression of the AR transcript variants 1 (AR1) and 2 (AR2) was measured.

Results

Regarding subtypes, high AR mRNA levels were frequent in HER2-positive (61.3%, 92/150) and luminal tumours (60.0%, 96/160) but almost absent in triple-negative tumours (4.3%, 3/69) (p < 0.0001). Overall, high AR mRNA levels were found to be associated with lower pathological complete remission (pCR) rates (OR 0.77 per unit, 95% CI 0.67–0.88, p  =  0.0002) but also with better prognosis in terms of longer disease-free survival (DFS) (HR 0.57, 95% CI 0.39–0.85, p  =  0.0054) and overall survival (OS) (HR 0.43, 95% CI, 0.26–0.71, p  =  0.0011). In the PREPARE trial, a survival difference for patients with high and low AR1 mRNA levels could only be seen in the standard chemotherapy arm but not in the dose-dense treatment arm (OS: HR 0.41; 95% CI 0.22–0.74 vs. HR 1.05; 95% CI 0.52–2.13; p  =  0.0459).

Conclusions

We provide evidence that AR mRNA predicts response to chemotherapy in breast cancer patients.

Consideration of breast cancer subtype in targeting the androgen receptor

The androgen receptor (AR) is a drug target in breast cancer, and AR-targeted therapies have induced tumor responses in breast cancer patients. In this review, we summarized the role of AR in breast cancer based on preclinical and clinical data. Response to AR-targeted therapies in unselected breast cancer populations is relatively low. Preclinical and clinical data show that AR antagonists might have a role in estrogen receptor (ER)-negative/AR-positive tumors. The prognostic value of AR for patients remains uncertain due to the use of various antibodies and cut-off values for immunohistochemical assessment. To get more insight into the role of AR in breast cancer, we additionally performed a retrospective pooled analysis to determine the prognostic value of the AR using mRNA profiles of 7270 primary breast tumors. Our analysis shows that a higher AR mRNA level is associated with improved disease outcome in patients with ER-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors, but with worse disease outcome in HER2-positive subgroups. In conclusion, next to AR expression, incorporation of additional tumor characteristics will potentially make AR targeting a more valuable therapeutic strategy in breast cancer.

Immunohistochemical Expression of Androgen Receptors (AR) in Various Breast Cancer Subtypes

BACKGROUND:

Breast carcinoma ranks the first among malignant tumours in females and is the chief cause of cancer-related mortality. Androgen in implicated in the induction of proliferation and growth of mammary cells through binding to their corresponding receptors. Androgens influence the risk of acquiring breast cancer through either direct binding to androgen receptors (AR) or indirectly through their transformation to estradiol or competing for steroid binding proteins.

AIM:

To study the expression of AR in various breast cancer subtypes and to elucidate its clinical significance by correlating it with clinicopathological parameters.

METHODS:

One hundred and fifty breast cancer cases were studied using AR immunohistochemistry, and its expression was correlated with different clinicopathologic parameters and with ER, PR, Her-2/neu and Ki 67 expression.

RESULTS:

AR was expressed in 91 breast carcinoma cases out of 150 examined. There was a statistically significant correlation between AR expression and tumour size, mitotic count, tumour necrosis, infiltrative borders, the hormonal status of the tumour and subsequently luminal subtypes (p < 0.05). A subset of studied TNBC (34.6%) also expressed AR. On the other hand, there was no significant correlation between AR expression and other clinicopathological parameters.

CONCLUSION:

Positive AR immunostaining was associated with favourable prognostic factors and luminal subtypes (A&B). Also, a subset of TNBC cases showed positive AR expression. These results introduce the current potent, next-generation AR- antagonist as possible target therapy in breast cancer. Further researches on AR expression in breast cancer are recommended on a larger scale with follow up and survival to validate the current results.

Prognostic and predictive value of androgen receptor expression in postmenopausal women with estrogen receptor-positive breast cancer: results from the Breast International Group Trial 1-98

BACKGROUND

The androgen receptor (AR) is an emerging prognostic marker and therapeutic target in breast cancer. AR is expressed in 60-80% of breast cancers, with higher prevalence among estrogen receptor-positive (ER+) tumors. Androgen treatment inhibits ER signaling in ER+/AR+ breast cancer cell lines, and AR expression is associated with improved survival for this subtype in epidemiologic studies. However, whether AR expression modifies the efficacy of selective ER modulators or aromatase inhibitors for ER+ cancers remains unclear.

METHODS

We evaluated the prognostic and predictive value of AR expression among 3021 postmenopausal ER+ breast cancer patients in the Breast International Group (BIG) trial 1-98. The BIG 1-98 study was a four-armed, double-blind, phase III randomized clinical trial that compared 5 years of tamoxifen or letrozole monotherapy, or sequences of 2 years and 3 years treatment with one drug and then the other. AR expression was measured by immunohistochemistry and the percentage of AR-positive nuclei was quantified. The association between AR expression and prognosis was evaluated using Cox proportional hazards models. Continuous AR-by-treatment interactions were assessed using Subpopulation Treatment Effect Pattern Plots (STEPP).

RESULTS

Eighty-two percent of patients had AR+ (≥ 1%) tumors. Patients with AR+ cancers were more likely to have smaller, lower-grade tumors, with higher expression of ER and PR. AR expression was not associated with breast cancer-free interval (BCFI) (415 events) over a median 8.0 years of follow-up (p = 0.12, log-rank test). In multivariable-adjusted models, AR expression was not associated with BCFI (HR = 1.07, 95% CI 0.83-1.36, p = 0.60). The letrozole versus tamoxifen monotherapy treatment effect did not significantly differ for AR+ tumors (HR = 0.63, 95% CI 0.44-0.75, p = 0.003) and AR- tumors (HR = 0.39, 95% CI 0.21-0.72, p = 0.002) (p-heterogeneity = 0.16). STEPP analysis also suggested no heterogeneity of the treatment effect across the continuum of AR expression.

CONCLUSIONS

AR expression was not associated with prognosis, nor was there heterogeneity of the letrozole versus tamoxifen treatment effect by AR expression. These findings suggest that AR expression may not be an informative biomarker for the selection of adjuvant endocrine therapy for postmenopausal women with ER+ breast cancers.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT00004205, Registered 27 January 2003-Retrospectively registered, https://clinicaltrials.gov/ct2/show/study/NCT00004205 .

Androgen receptor expression in normal breast tissue and subsequent breast cancer risk

Sex steroid hormone signaling is critical in the development of breast cancers, although the role of the androgen receptor remains unclear. This study evaluated androgen receptor (AR) expression in normal breast tissue as a potential marker of breast cancer risk. We conducted a nested case-control study of women with benign breast disease (BBD) within the Nurses' Health Studies. Epithelial AR expression was assessed by immunohistochemistry in normal tissue from the BBD biopsy and the percent of positive nuclei was estimated in ordinal categories of 10% for 78 breast cancer cases and 276 controls. Logistic regression models adjusting for the matching factors and BBD lesion type were used to calculate odds ratios (ORs) for the association between AR expression (tertiles: ≤10%, 11-30%, and >30%) and breast cancer risk. AR expression in normal breast tissue was not associated with subsequent breast cancer risk (OR_T3vsT1 = 0.9, 95% CI = 0.4-1.8, p trend = 0.68). In comparison with low AR/low ER women, ORs of 0.4 (95% CI = 0.1-1.2) for high AR/high ER women, 1.8 (95% CI = 0.4-7.8) for low AR/high ER women, and 0.7 (95% CI = 0.3-1.6) for high AR/low ER women were observed (p interaction = 0.21). Ki67 did not modify the association between AR expression and breast cancer risk (p interaction = 0.75). There was little evidence for an overall association between AR expression in normal breast tissue and breast cancer risk. These findings did not show that the AR association varied by Ki67 expression in normal breast tissue, though there was suggestive heterogeneity by ER expression.

The cellular and molecular effects of the androgen receptor agonist, Cl-4AS-1, on breast cancer cells

PURPOSE

The androgen receptor (AR) has attracted attention in the treatment of breast cancer. Due to the undesirable side effects of AR agonists, attempts have been undertaken to develop selective AR modulators. One of these compounds is Cl-4AS-1. This study examined this compound more closely at the cellular and molecular levels.

METHODS

Three different breast cancer cell lines were utilized, namely the luminal MCF-7 cells, the molecular apocrine MDA-MB-453 cells, and the triple negative, basal MDA-MB-231 cells.

RESULTS

High and significant concordance between dihydrotestosterone (DHT) and Cl-4AS-1 in regulation of gene expression in MDA-MB-453 cells was found. However, some differences were noted including the expression of AR, which was upregulated by DHT, but not Cl-4AS-1. In addition, both DHT and Cl-4AS-1 caused a similar morphological change and reorganization of the actin structure of MDA-MB-453 cells into a mesenchymal phenotype. Treatment of cells with DHT resulted in induction of proliferation of MCF-7 and MDA-MB-453 cells, but no effect was observed on the growth of MDA-MB-231 cells. On the other hand, increasing doses of Cl-4AS-1 resulted in a dose-dependent inhibition on the growth of the three cell lines. This inhibition was a result of induction of apoptosis whereby Cl-4AS-1 caused a block in entry of cells into the S-phase followed by DNA degradation.

CONCLUSIONS

These results indicate that although Cl-4AS-1 has characteristics of classical AR agonist, it has dissimilar properties that may make it useful in treating breast cancer.

Dihydrotestosterone and cancer risk

PURPOSE OF REVIEW

Androgens have been implicated in prostate growth; however, the role of androgens in prostate cancer development is not clear. Furthermore, studies suggest a role for androgens in female-hormone-dependent cancers and common nonhormone dependent cancers. This study aims to review key studies and more recent studies of dihydrotestosterone (DHT) and cancer risk.

RECENT FINDINGS

Epidemiological studies are reassuring as they have not associated endogenous androgens with prostate cancer risk. Intraprostatic regulation of DHT is becoming recognized as an important area of research to clarify the role of DHT in prostate cancer development. In females, further understanding of intracrine regulation of sex hormones and interactions between androgens and estrogens in influencing breast and endometrial cancer risk are required. Studies show a signal for DHT in modulating lung and colorectal cancer growth; however, research in this area is relatively scarce and further studies are required to clarify these associations.

SUMMARY

Although concerns of prostate cancer risk remain, there is also potential for androgens to modulate the growth and development of other common cancers. Further research is required as this may have clinical implications.

Expression of hormone receptors in oropharyngeal squamous cell carcinoma

OBJECTIVES

Hormone receptors play an important role in many types of cancers. Alongside factors associated with human papillomavirus (HPV) infection, hormonal receptors may impact the tumorigenesis of oropharyngeal cancer.

MATERIALS AND METHODS

This study consists of 199 consecutive oropharyngeal squamous cell carcinoma (OPSCC) patients diagnosed and treated with a curative intent. We examined androgen (AR), estrogen (ER; both alpha and beta), and progesterone receptor (PR) expressions using immunohistochemistry comparing tumor and patient characteristics.

RESULTS

AR was expressed in 16%, PR in 27% and ER-beta in 63% of the tumors. HPV- and p16-positive tumors expressed more AR and less PR than their negative counterparts. High PR expression was associated with poor disease-specific and locoregional recurrence-free survival.

CONCLUSION

AR, PR, and ER-beta are expressed in OPSCC, and AR and PR expressions are associated with HPV and p16 status. Furthermore, PR appears to have prognostic significance. This may allow us to investigate the role of anti-hormone receptors in the treatment of OPSCC.

The Magnitude of Androgen Receptor Positivity in Breast Cancer Is Critical for Reliable Prediction of Disease Outcome

Purpose: Consensus is lacking regarding the androgen receptor (AR) as a prognostic marker in breast cancer. The objectives of this study were to comprehensively review the literature on AR prognostication and determine optimal criteria for AR as an independent predictor of breast cancer survival.Experimental Design: AR positivity was assessed by immunostaining in two clinically validated primary breast cancer cohorts [training cohort, n = 219; validation cohort, n = 418; 77% and 79% estrogen receptor alpha (ERα) positive, respectively]. The optimal AR cut-point was determined by ROC analysis in the training cohort and applied to both cohorts.Results: AR was an independent prognostic marker of breast cancer outcome in 22 of 46 (48%) previous studies that performed multivariate analyses. Most studies used cut-points of 1% or 10% nuclear positivity. Herein, neither 1% nor 10% cut-points were robustly prognostic. ROC analysis revealed that a higher AR cut-point (78% positivity) provided optimal sensitivity and specificity to predict breast cancer survival in the training (HR, 0.41; P = 0.015) and validation (HR, 0.50; P = 0.014) cohorts. Tenfold cross-validation confirmed the robustness of this AR cut-point. Patients with ERα-positive tumors and AR positivity ≥78% had the best survival in both cohorts (P < 0.0001). Among the combined ERα-positive cases, those with comparable or higher levels of AR (AR:ERα-positivity ratio >0.87) had the best outcomes (P < 0.0001).Conclusions: This study defines an optimal AR cut-point to reliably predict breast cancer survival. Testing this cut-point in prospective cohorts is warranted for implementation of AR as a prognostic factor in the clinical management of breast cancer. Clin Cancer Res; 24(10); 2328-41. ©2018 AACR.

The role of the AR/ER ratio in ER-positive breast cancer patients

The significance of androgen receptor (AR) in breast cancer (BC) management is not fully defined, and it is still ambiguous how the level of AR expression influences oestrogen receptor-positive (ER+) tumours. The aim of the present study was to analyse the prognostic impact of AR/ER ratio, evaluated by immunohistochemistry (IHC), correlating this value with clinical, pathological and molecular characteristics. We retrospectively selected a cohort of 402 ER+BC patients. On each tumour, IHC analyses for AR, ER, PgR, HER2 and Ki67 were performed and AR+ cases were used to calculate the AR/ER value. A cut-off of ≥2 was selected using receiver-operating characteristic (ROC) curve analyses. RNA from 19 cases with AR/ER≥2 was extracted and used for Prosigna-PAM50 assays. Tumours with AR/ER≥2 (6%) showed more frequent metastatic lymph nodes, larger size, higher histological grade and lower PgR levels than cases with AR/ER<2. Multivariate analysis confirmed that patients with AR/ER≥2 had worse disease-free interval (DFI) and disease-specific survival (DSS) (hazard ratios (HR) = 4.96 for DFI and HR = 8.69 for DSS, both P ≤ 0.004). According to the Prosigna-PAM50 assay, 63% (12/19) of these cases resulted in intermediate or high risk of recurrence categories. Additionally, although all samples were positive for ER assessed by IHC, the molecular test assigned 47.4% (9/19) of BCs to intrinsic non-luminal subtypes. In conclusion, the AR/ER ratio ≥2 identifies a subgroup of patients with aggressive biological features and may represent an additional independent marker of worse BC prognosis. Moreover, the Prosigna-PAM50 results indicate that a significant number of cases with AR/ER≥2 could be non-luminal tumours.

Androgen receptor/let-7a signaling regulates breast tumor-initiating cells

Androgen receptor (AR) is an important transcriptional factor, which is frequently expressed in invasive breast cancer and correlates patients’ prognosis. Our previous results indicate AR activation may increase let-7a expression in breast cancer cells, while let-7, a tumor suppressor, is reported to inhibit breast tumor-initiating cells (T-IC). The study aims to explore the effects of AR/let-7a signaling on breast T-IC and its regulatory mechanism. The results revealed that the expression of AR was significantly associated with let-7a and CD44⁺/24^-/low especially in estrogen receptor positive (ER+) breast cancer tissues. The expression of AR and let-7a indicated better outcome, while patients with CD44⁺/24^-/low phenotype had worse prognosis. AR activation induced by dihydrotestosterone (DHT) prevented cells proliferation, migration, invasion and self-renewal capacities in ER+ breast cancer cells, via transcriptional up-regulation of let-7a. In addition, AR could inhibit tumorigenesis and metastasis of ER+ breast cancer cells in the serial xenotranplanted animal models. Our data suggested that AR/let-7a signaling could inhibit the biological behavior of tumor-initiating cells (T-IC) in ER+AR+ breast cancers, which might become a new therapeutic target.

Expression of Androgen Receptor in Estrogen Receptor-positive Breast Cancer

Objectives:

The aim of the study was to estimate the implications of androgen receptor (AR) expression in estrogen receptor (ER)-positive subset of invasive breast carcinoma patients.

Patients and Methods:

We assessed the AR expression in a subset of 96 predominantly ER-positive invasive breast carcinomas and correlated this expression pattern with several clinical and pathologic parameters: histologic type and grade, tumor size, lymph node status, progesterone receptor (PgR) status, and human epidermal growth factor receptor type 2 (HER2) overexpression and evaluated the association of these parameters with 10-year survival using univariate and multivariate analyses. Data used for analysis were derived from medical records. Immunohistochemical analysis for AR, ER, PgR, and HER2 were carried out and semiquantitative evaluation of stainings was performed.

Results:

AR expression was demonstrated in 43.7% of patients. AR was significantly related to well-differentiated tumors and positive PgR/HER2 status. No statistical difference was demonstrated in AR expression in relation to tumor size, lymph node status, menopausal status, and tumor histologic type. AR expression was not an independent prognostic factor related to 10-year survival in ER-positive cancers. In multivariate analyses, older age at diagnosis, larger tumor size, and positive lymph node status were significantly associated with poorer 10-year survival.

Conclusions:

AR expression is significantly associated with ER/PgR/HER2 status and positively related to well-differentiated tumors. Although AR status in ER-positive cancers is not an independent prognostic factor, it might provide important additional information on prognosis and become a promising object for targeted therapy.

Androgen Receptor Expression in an Indian Breast Cancer Cohort with Relation to Molecular Subtypes and Response to Neoadjuvant Chemotherapy - a Prospective Clinical Study

BACKGROUND

Breast cancer (BC) is associated with advanced presentation in developing countries like India due to various socio-economic factors. The presence of BC molecular subtypes such as the triple-negative (TN) subtype adds to this menace. Androgen receptor (AR) is emerging as a new biological marker. The aim of this study was to examine the prevalence of AR with relation to different BC subtypes, and its role in predicting response to neoadjuvant chemotherapy.

METHODS

116 cases of invasive BC (infiltrating ductal carcinoma, not otherwise specified) were evaluated. AR expression was correlated with clinicopathological factors, established prognostic markers, BC subtypes and it ability for predicting response to neoadjuvant chemotherapy.

RESULTS

AR was expressed in 56% of the cases. AR expression was significantly associated with early stage (p < 0.03), low axillary burden (p < 0.04), estrogen receptor (p = 0.002), progesterone receptor (p = 0.001) expression and luminal A molecular subtype. No significant association was observed with age, tumor size and HER2/neu status. One-third of TNBC cases expressed AR. Higher AR expression corelated to good clinical response to neoadjuvant chemotherapy.

CONCLUSION

AR can be utilized as a predictor of response to neoadjuvant chemotherapy especially in developing countries such as India where the load of advanced disease is high.

In vitro and in vivo effect of flutamide on steroid hormone secretion in canine and human inflammatory breast cancer cell lines

The aim was to study the effects of flutamide on cell proliferation, in vivo tumour growth and steroid production in canine and human IBC cell lines. IPC-366 and SUM149 cell cultures were exposed to flutamide concentrations for 72 hours. Additionally, IPC-366 and SUM149 xenotransplanted mice were treated subcutaneously with flutamide 3 times a week for 2 weeks. Steroid hormones determination in culture media, serum and tumour homogenates (pregnenolone, progesterone, androstenedione, testosterone, dihydrotestosterone, 17β-oestradiol and oestrone sulphate) were assayed by EIA. in vitro cell proliferation percentages showed a decrease in all flutamide dosages in IPC-366 and SUM149. in vivo flutamide reduced tumour size by 55% to 65%, and metastasis rates decreased. In treated groups, androgen levels in culture media, serum and tumour homogenates were increased as oestrogen levels decreased. These results suggest that flutamide treatment inhibits cell proliferation and promotes tumour reduction by increasing androgen levels and also support future therapy approaches.

MMTV-PyMT and Derived Met-1 Mouse Mammary Tumor Cells as Models for Studying the Role of the Androgen Receptor in Triple-Negative Breast Cancer Progression

Triple-negative breast cancer (TNBC) has a faster rate of metastasis compared to other breast cancer subtypes, and no effective targeted therapies are currently FDA-approved. Recent data indicate that the androgen receptor (AR) promotes tumor survival and may serve as a potential therapeutic target in TNBC. Studies of AR in disease progression and the systemic effects of anti-androgens have been hindered by the lack of an AR-positive (AR+) immunocompetent preclinical model. In this study, we identified the transgenic MMTV-PyMT (mouse mammary tumor virus-polyoma middle tumor-antigen) mouse mammary gland carcinoma model of breast cancer and Met-1 cells derived from this model as tools to study the role of AR in breast cancer progression. AR protein expression was examined in late-stage primary tumors and lung metastases from MMTV-PyMT mice as well as in Met-1 cells by immunohistochemistry (IHC). Sensitivity of Met-1 cells to the AR agonist dihydrotestosterone (DHT) and anti-androgen therapy was examined using cell viability, migration/invasion, and anchorage-independent growth assays. Late-stage primary tumors and lung metastases from MMTV-PyMT mice and Met-1 cells expressed abundant nuclear AR protein, while negative for estrogen and progesterone receptors. Met-1 sensitivity to DHT and AR antagonists demonstrated a reliance on AR for survival, and AR antagonists inhibited invasion and anchorage-independent growth. These data suggest that the MMTV-PyMT model and Met-1 cells may serve as valuable tools for mechanistic studies of the role of AR in disease progression and how anti-androgens affect the tumor microenvironment.

A Tale of Two Signals: AR and WNT in Development and Tumorigenesis of Prostate and Mammary Gland

Prostate cancer (PCa) is one of the most common cancers and among the leading causes of cancer deaths for men in industrialized countries. It has long been recognized that the prostate is an androgen-dependent organ and PCa is an androgen-dependent disease. Androgen action is mediated by the androgen receptor (AR). Androgen deprivation therapy (ADT) is the standard treatment for metastatic PCa. However, almost all advanced PCa cases progress to castration-resistant prostate cancer (CRPC) after a period of ADT. A variety of mechanisms of progression from androgen-dependent PCa to CRPC under ADT have been postulated, but it remains largely unclear as to when and how castration resistance arises within prostate tumors. In addition, AR signaling may be modulated by extracellular factors among which are the cysteine-rich glycoproteins WNTs. The WNTs are capable of signaling through several pathways, the best-characterized being the canonical WNT/β-catenin/TCF-mediated canonical pathway. Recent studies from sequencing PCa genomes revealed that CRPC cells frequently harbor mutations in major components of the WNT/β-catenin pathway. Moreover, the finding of an interaction between β-catenin and AR suggests a possible mechanism of cross talk between WNT and androgen/AR signaling pathways. In this review, we discuss the current knowledge of both AR and WNT pathways in prostate development and tumorigenesis, and their interaction during development of CRPC. We also review the possible therapeutic application of drugs that target both AR and WNT/β-catenin pathways. Finally, we extend our review of AR and WNT signaling to the mammary gland system and breast cancer. We highlight that the role of AR signaling and its interaction with WNT signaling in these two hormone-related cancer types are highly context-dependent.

Androgen and AR contribute to breast cancer development and metastasis: an insight of mechanisms

The role of androgen and androgen receptor (AR) in breast carcinogenesis has long been a disputed issue. This report provides a mechanistic insight into how androgen and AR contributes to invasion and metastasis of breast cancer. We find that dihydrotestosterone (DHT) is able to induce the epithelial-to-mesenchymal transition in breast cancer cells in an AR-dependent/estrogen receptor-independent manner. This process is dependent on the demethylation activity of lysine-specific demethylase 1A (LSD1) by epigenetically regulating the target genes E-cadherin and vimentin. In vivo, DHT promotes metastasis in a nude mouse model, and AR and LSD1 are indispensable in this process. We establish that higher expression of nucleus AR to cytoplasm AR associated with worse prognostic outcomes in breast cancer patient samples. This study maps an 'androgen-AR/LSD1-target genes' pathway in breast carcinogenesis, implicating the importance of hormonal balance in women, and the potential clinical significance of serum androgen and AR in prediction of breast cancer and selection of breast cancer therapy.

Androgen Receptor Expression in Breast Carcinoma of Egyptian Patients

INTRODUCTION

Breast carcinoma (BC) is a heterogeneous disease, with distinctive molecular sub-types, influencing BC patients prognosis and therapeutic options. Androgen Receptor (AR) is a steroid nuclear receptor involved in complex signaling pathways, that are thought to play a role in cell proliferation. AR expression in relation to different molecular sub-types of BC is not clearly understood.

AIM

The aim of this study was to evaluate the expression of AR in BC from Egyptian patients and correlate it with the standard clinico-pathologic variables, molecular sub-type of BC and the Overall Survival (OS).

MATERIALS AND METHODS

This retrospective study was conducted on 81 cases of BC from egyptian patients, stained immunohistochemically with AR. Chi-Square and Kaplan-Meier tests were applied to study the correlation between AR expression and clinicopathologic variables and the OS of BC patients respectively.

RESULTS

Among studied BC cases, 37.04% were immunoreactive to AR. AR immunoreactivity was significantly corrrelated with older age (p=0.03), post-menopausal status (p=0.001), lower grade (p=0.003), the presence of in-situ component (p= 0.014), early stage of presentation (p=0.03) and good-moderate NPI (0.009). It was also correlated with Positive ER, negative HER-2/neu, low Ki-67 proliferation index and luminal A subtype. AR expression didn't correlate with the OS in the studied cases.

CONCLUSION

AR was found to be related to favourable prognostic factors in BC but not to OS. It was particularly expressed in luminal A group and in significant proportion in Triple Negative Breast Carcinoma (TNBC), providing an opportunity for AR targeted therapy.

Androgen Receptor as a Potential Target for Treatment of Breast Cancer

Clinical studies have shown that the androgen receptor (AR) is ubiquitously expressed in breast cancers and this could provide prognostic implication in the diagnosis and treatment of breast cancers. Data from Nurse’s Health Study on women with invasive breast cancer suggest that a significant number of tumors were AR-positive as defined by immunohistochemistry. In addition, the distribution of AR among different breast cancer subtypes varies significantly, and the biological reasons for this variation are not well understood. Despite strong histochemical evidence, the AR status is not applied for assessing pathological findings and disease outcome in clinical practice. AR antagonists are not currently used as therapy in breast cancer. This is in part due to conflicting results from early clinical trials with first generation of AR antagonists together with the complexity in breast cancer heterogeneity. In addition, role of AR in breast cancer is not fully understood. Here we will review the role of AR in different subtypes of breast cancers and elucidate its mechanisms. We will also discuss some recent interesting findings on the second generation of AR antagonists for treatment of breast cancer.

Androgen Receptor Expression in Thai Breast Cancer Patients

The aim of this study was to investigate prevalence and related factors of androgen receptor (AR) expression in Thai breast cancer patients. A descriptive study was done in 95 patients, who were admitted to Charoenkrung Pracharak Hospital, Bangkok (2011-2013). Statistical relationships were examined between AR protein expression, tumor status, and patient characteristics. Compared with those from Western countries, ethnic Thai patients were younger at age of diagnosis and had a higher proliferative index (high Ki-67 expression), which indicates unfavorable prognosis. In addition, 91% of the Thai breast tumors that were positive for any of the following receptors, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) also expressed the AR protein, while in triple negative breast tumors only 33% were AR positive. ER and PR expression was positively related with AR expression, while AR expression was inversely correlated to Ki-67 expression. AR status was strongly correlated with ER and PR status in Thai patients. There is an inverse relationship between Ki-67 and AR, which suggests that AR may be a prognostic factor for breast cancer.

Prognostic significance of androgen receptor expression in invasive breast cancer: transcriptomic and protein expression analysis

Differential prognostic roles of Androgen Receptor (AR) have been proposed in breast cancer (BC) depending on tumour oestrogen receptor (ER) status. This study aimed to evaluate the prognostic and/or predictive significance of AR expression in invasive BC. In this study AR expression was studied on a large (n = 1141) consecutive series of early-stage (I-III) BC using tissue microarray and immunohistochemistry (IHC). AR mRNA expression was assessed in a subset of cases. The prognostic impact of AR mRNA expression was externally validated using the online BC gene expression data sets (n = 25 data sets, 4078 patients). Nuclear AR IHC expression was significantly associated with features of good prognosis including older age, smaller tumour size, lower grade and lobular histology particularly in the ER-positive tumours. AR was associated with ER-related markers GATA3, FOXa1, RERG and BEX1. Negative association was observed with HER2, p53, Ki67, TK1, CD71 and AGTR1. AR Overexpression was associated with longer survival (p < 0.001), independent of tumour size, grade, stage [p = 0.033, hazard ratio (HR) = 0.80 95 % CI = 0.64-0.98]. Similar associations were maintained in ER+ tumours in univariate and multivariate analysis (p < 0.01) both in patients with and without adjuvant endocrine or chemotherapy. AR mRNA expression showed significant association with tumour grade, molecular subtypes, and longer 10 and 15 years survival in luminal BC. In the external validation cohorts, AR gene expression data were associated with improved patients' outcome (p < 0.001, HR = 0.84, 95 % CI 0.79-0.90). AR is not only an independent prognostic factor in ER-positive luminal BC but is also expressed in ER-negative tumours. AR could act as a molecular target in patients with ER-positive disease predicting response to adjuvant therapy.

Emerging therapeutic targets in metastatic progression: A focus on breast cancer

Metastasis is the underlying cause of death for the majority of breast cancer patients. Despite significant advances in recent years in basic research and clinical development, therapies that specifically target metastatic breast cancer remain inadequate, and represents the single greatest obstacle to reducing mortality of late-stage breast cancer. Recent efforts have leveraged genomic analysis of breast cancer and molecular dissection of tumor-stromal cross-talk to uncover a number of promising candidates for targeted treatment of metastatic breast cancer. Rational combinations of therapeutic agents targeting tumor-intrinsic properties and microenvironmental components provide a promising strategy to develop precision treatments with higher specificity and less toxicity. In this review, we discuss the emerging therapeutic targets in breast cancer metastasis, from tumor-intrinsic pathways to those that involve the host tissue components, including the immune system.

Role of the androgen receptor in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive disease with outcomes inferior to those of other breast cancer subtypes. No targeted therapies are currently approved for TNBC, and newer treatment approaches are critically needed. It is increasingly recognized that TNBC is a heterogeneous disease, and the role of androgen signaling in a subset of TNBC is emerging. Although the degree of androgen receptor (AR) expression in TNBC varies widely depending on the assay methodology, cutoff for positivity, and patient population, existing evidence suggests an association between a higher level of AR expression and improved outcomes. Despite lower pathologic complete response (pCR) rates with neoadjuvant therapy, patients with AR-dependent TNBCs have a better prognosis than those with TNBCs that are not AR-dependent. Furthermore, gene expression profiling has been used to identify a luminal androgen receptor subtype of TNBC that is dependent on AR signaling. Early clinical studies investigating agents targeting AR in advanced TNBC have produced promising results. We review herein the literature on the biology of AR in breast cancer and its prognostic and predictive role in TNBC, and we describe the results of early clinical trials with antiandrogens in this population. We also present our vision of the future development of newer therapeutic strategies in AR-dependent TNBC.

Androgen deprivation by adrenal suppression using low-dose hydrocortisone for the treatment of breast carcinoma with apocrine features: a case report illustrating this new paradigm

We report on a postmenopausal patient with a secondary metastatic apocrine breast cancer successfully treated with low-dose hydrocortisone only following several lines of chemotherapy. The tumor cells in the primary and metastatic lesion exhibited a 'triple-negative' status (estrogen receptor (ER)-, progesterone receptor (PR)-, and human epidermal growth factor receptor 2 (HER2)-negative); the androgen receptor (AR) was strongly expressed. Twenty milligrams of hydrocortisone, a low substitution dose known to suppress adrenal steroid production, twice daily led to a clinical benefit lasting for one year, with symptom control, radiologically stable disease, and steady decrease in CA15.3. Our observation demonstrates that an AR-expressing apocrine breast cancer may respond to androgen deprivation, as an ER-positive breast cancer may benefit from estrogen deprivation. It highlights the importance of further research targeting the AR pathway in apocrine carcinoma, for which androgens represent the sole (known) steroid hormone stimulating tumor growth. Future clinical trials should not only focus on AR inhibitors like enzalutamide, but also on ablative modalities like low-dose hydrocortisone aiming at medical adrenalectomy. This method of androgen deprivation is largely available, cheap, and nearly devoid of toxicity.