Androgen Receptor: A Complex Therapeutic Target for Breast Cancer

Identification of novel chemical scaffolds against kinase domain of cancer causing human epidermal growth factor receptor 2: a systemic chemoinformatic approach

The Human epidermal growth factor receptor 2 (HER2) is expressed in high magnitude in several cancers. Designing new drug molecules that target kinase domain of the HER2 enzyme might provide an appealing platform. Considering this, herein, a multi-phase bioinformatic approach is applied to screen diverse natural and chemical scaffolds to identify compounds that fit best at the kinase domain of HER2. By doing so, three compounds; LAS_51187157, LAC_51217113, LAC_51390233 were pointed with docking score of -11.4 kcal/mol, -11.3 kcal/mol and -11.2 kcal/mol, respectively. In molecular dynamic simulation, the complexes behaved in a stable dynamic with no major local/global structural variations. The intermolecular binding free energies were further estimated that concluded LAC_51390233 complex was the most stable and has less entropy energy. The good docked affinity of LAC_51390233 with HER2 was confirmed by WaterSwap absolute binding free energy. The entropy energy demonstrated that LAC_51390233 has less freedom energy compared to others. Similarly, all three compounds revealed very favorable druglike properties and pharmacokinetics. All the selected three compounds were also non-carcinogenic, non-immunotoxicity, non-mutagenicity, and non-cytotoxic. In a nutshell, the compounds are interesting scaffolds and might be subjected to extensive experimental testing to reveal their real biological potency.Communicated by Ramaswamy H. Sarma.

Molecular Imaging of Steroid Receptors in Breast Cancer

ABSTRACT

Steroid receptors regulate gene expression for many important physiologic functions and pathologic processes. Receptors for estrogen, progesterone, and androgen have been extensively studied in breast cancer, and their expression provides prognostic information as well as targets for therapy. Noninvasive imaging utilizing positron emission tomography and radiolabeled ligands targeting these receptors can provide valuable insight into predicting treatment efficacy, staging whole-body disease burden, and identifying heterogeneity in receptor expression across different metastatic sites. This review provides an overview of steroid receptor imaging with a focus on breast cancer and radioligands for estrogen, progesterone, and androgen receptors.

HDAC inhibitors target IRS4 to enhance anti‑AR therapy in AR‑positive triple‑negative breast cancer

Triple‑negative breast cancer (TNBC) is the most malignant subtype of breast cancer. Androgen receptor (AR) has been identified as a potential therapeutic target for AR‑positive TNBC; however, clinical trials have not yet produced an effective treatment. The present study aimed to identify a novel treatment regimen to improve the prognosis of AR‑positive TNBC. First, a combination of an AR inhibitor (enzalutamide, Enz) and a selective histone deacetylase inhibitor (chidamide, Chid) was used to treat AR‑positive TNBC cell lines, and a synergistic effect of these drugs was observed. The combination treatment inhibited cell proliferation and migration by arresting the cell cycle at the G2/M phase. Subsequently, next‑generation sequencing was performed to detect changes in gene regulation. The results showed that the PI3K/Akt signalling pathway was significantly inhibited by the combination treatment of Enz and Chid. Gene Set Enrichment Analysis revealed that the combination group was significantly enriched in KRAS signalling. Analysis of the associated genes revealed that insulin receptor substrate 4 (IRS4) may have a critical role in blocking the activation of KRAS signalling. In a mouse xenograft model, combination treatment also inhibited the PI3K/Akt signalling pathway by upregulating the expression of IRS4 and thereby suppressing tumour growth. In conclusion, the results of the present study revealed that combination treatment with Enz and Chid can upregulate IRS4, which results in the blocking of KRAS signalling and suppression of tumour growth. It may be hypothesised that the expression levels of IRS4 could be used as a biomarker for screening patients with AR‑positive TNBC using Enz and Chid combination therapy.

Treatments Targeting the Androgen Receptor and Its Splice Variants in Breast Cancer

Breast cancer is a major cause of death worldwide. The complexity of endocrine regulation in breast cancer may allow the cancer cells to escape from a particular treatment and result in resistant and aggressive disease. These breast cancers usually have fewer treatment options. Targeted therapies for cancer patients may offer fewer adverse side effects because of specificity compared to conventional chemotherapy. Signaling pathways of nuclear receptors, such as the estrogen receptor (ER), have been intensively studied and used as therapeutic targets. Recently, the role of the androgen receptor (AR) in breast cancer is gaining greater attention as a therapeutic target and as a prognostic biomarker. The expression of constitutively active truncated AR splice variants in breast cancer is a possible mechanism contributing to treatment resistance. Therefore, targeting both the full-length AR and AR variants, either through the activation or suppression of AR function, depending on the status of the ER, progesterone receptor, or human epidermal growth factor receptor 2, may provide additional treatment options. Studies targeting AR in combination with other treatment strategies are ongoing in clinical trials. The determination of the status of nuclear receptors to classify and identify patient subgroups will facilitate optimized and targeted combination therapies.

Targeting androgen receptor in glioblastoma

Glioblastomas are primary brain tumors that originate from glial stem cells or progenitor cells. There is a large difference in the incidence of glioblastoma between males and females. Studies revealed that the gender differences in the tumor may be attributable to the androgen receptor signaling axis. The incidence rate of glioblastoma in men is higher than that in women. Aberrant activation of the androgen receptor signaling pathway, or interactions between the androgen receptor signaling axis and other signaling axes promote the development of glioblastoma. Therefore, targeting the androgen receptor holds promise as a therapeutic approach for glioblastoma. This review investigates the dynamics of drug research into the treatment of glioblastoma by targeting the androgen receptor. The first finding in line with expectations is that androgen receptor antagonists, represented by enzalutamide, have been studied and shown to have anti-glioblastoma effects. In addition, it was found that the combination of 5-alpha reductase inhibitors and androgen receptor antagonists resulted in better therapeutic outcomes than each of them alone. Similar results were obtained with the combination of an epidermal growth factor receptor inhibitor and an androgen receptor antagonist. In addition, four small molecule compounds have been shown to exert significant anti-glioblastoma effects by directly or indirectly targeting the androgen receptor. Expectantly, one of these small molecules, seviteronel, progressed to the phase II clinical trial stage. These findings suggest that targeting the androgen receptor for glioblastoma may be a promising therapeutic option.

Molecular Biology Mechanisms and Emerging Therapeutics of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is conventionally characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2), accounting for approximately 15-20% of all breast cancers. Compared to other molecular phenotypes, TNBC is typically associated with high malignancy and poor prognosis. Cytotoxic agents have been the mainstay of treatment for the past few decades due to the lack of definitive targets and limited therapeutic interventions. However, recent developments have demonstrated that TNBC has peculiar molecular classifications and biomarkers, which provide the possibility of evolving treatment from basic cytotoxic chemotherapy to an expanding domain of targeted therapies. This review presents a framework for understanding the current clinical experience surrounding molecular biology mechanisms in TNBC (Figure 1). Including immunotherapy, polymerase (PARP) and PI3K/AKT pathway inhibitors, antibody-drug conjugates, and androgen receptor (AR) blockade. Additionally, the role of miRNA therapeutics targeting TNBC and potential strategies targeting cancer stem cells (CSCs) are discussed and highlighted. As more and more treatments arise on the horizon, we believe that patients with TNBC will have a new sense of hope.

[18F]-FDHT PET for the Imaging of Androgen Receptor in Prostate and Breast Cancer: A Systematic Review

The aim of this systematic review is to provide a comprehensive overview of the role of fluoro-5α-dihydrotestosterone ([18F]-FDHT) for the in vivo imaging of androgen receptors (AR) through positron emission tomography (PET) in metastatic breast (mBC) and metastatic castration-resistant prostate cancer (mCRPC). Relevant studies published from 2013 up to May 2023 were selected by searching Scopus, PubMed and Web of Science. The selected imaging studies were analyzed using a modified version of the critical Appraisal Skills Programme (CASP). Eleven studies encompassing 321 patients were selected. Seven of the eleven selected papers included 266 subjects (82.2%) affected by mCRPC, while four encompassed 55 (17.2%) patients affected by mBC. [18F]-FDHT PET showed a satisfying test/retest reproducibility, and when compared to a histochemical analysis, it provided encouraging results for in vivo AR quantification both in mCRPC and mBC. [18F]-FDHT PET had a prognostic relevance in mCRPC patients submitted to AR-targeted therapy, while a clear association between [18F]-FDHT uptake and the bicalutamide response was not observed in women affected by AR-positive mBC. Further studies are needed to better define the role of [18F]-FDHT PET, alone or in combination with other tracers (i.e., [18F]-FDG/[18F]-FES), for patients' selection and monitoring during AR-targeted therapy, especially in the case of mBC.

Androgen Receptor Status in Triple Negative Breast Cancer: Does It Correlate with Clinicopathological Characteristics?

Purpose

Triple negative breast cancer (TNBC) is a breast carcinoma subtype that neither expresses estrogen (ER) and progesterone receptors (PR) nor the human epidermal growth factor receptor 2 (HER2). Patients with TNBC have been shown to have poorer outcomes mainly owing to the limited treatment options available. However, some studies have shown TNBC tumors expressing androgen receptors (AR), raising hopes of its prognostic role.

Patients and Methods

This retrospective study investigated the expression of AR in TNBC and its relationship with known patient demographics, tumor and survival characteristics. From the records of 205 TNBC patients, 36 had available archived tissue samples eligible for AR staining. For statistical purposes, tumors were classified as either "positive" or "negative" for AR expression. The nuclear expression of AR was scored by measuring the percentage of stained tumor cells and its staining intensity.

Results

AR was expressed by 50% of the tissue samples in our TNBC cohort. The relationship between AR status with age at the time of TNBC diagnosis was statistically significant, with all AR positive TNBC patients being greater than 50 years old (vs 72.2% in AR negative TNBC). Also, the relationship between AR status and type of surgery received was statistically significant. There were no statistically significant associations between AR status with other tumor characteristics including "TNM status", tumor grade or treatments received. There was no statistically significant difference in median survival between AR negative and AR positive TNBC patients (3.5 vs 3.1 years; p = 0.581). The relationship between OS time and AR status (p = 0.581), type of surgery (p = 0.061) and treatments (p = 0.917) were not statistically significant.

Conclusion

The androgen receptor may be an important prognostic marker in TNBC, with further research warranted. This research may benefit future studies investigating receptor-targeted therapies in TNBC.

Nuclear Receptor Imaging In Vivo-Clinical and Research Advances

Nuclear receptors are transcription factors that function in normal physiology and play important roles in diseases such as cancer, inflammation, and diabetes. Noninvasive imaging of nuclear receptors can be achieved using radiolabeled ligands and positron emission tomography (PET). This quantitative imaging approach can be viewed as an in vivo equivalent of the classic radioligand binding assay. A main clinical application of nuclear receptor imaging in oncology is to identify metastatic sites expressing nuclear receptors that are targets for approved drug therapies and are capable of binding ligands to improve treatment decision-making. Research applications of nuclear receptor imaging include novel synthetic ligand and drug development by quantifying target drug engagement with the receptor for optimal therapeutic drug dosing and for fundamental research into nuclear receptor function in cells and animal models. This mini-review provides an overview of PET imaging of nuclear receptors with a focus on radioligands for estrogen receptor, progesterone receptor, and androgen receptor and their use in breast and prostate cancer.

Evolving Evidence for the Optimization of Neoadjuvant Therapy in Triple-Negative Breast Cancer

Representing 15% to 20% of all invasive breast cancers, adjuvant systemic treatment for early-stage, high-risk triple-negative breast cancer (TNBC) is preferentially done in the neoadjuvant setting based on a chemotherapy backbone of anthracyclines and taxanes. Pathological complete response to neoadjuvant treatment constitutes the main objective, regarding its correlation with oncological outcomes. The optimal neoadjuvant regimen to achieve the highest rates of pathological complete response is still under investigation, with the increasing knowledge on the molecular pathways, genomic sequencing, and immunological profile of TNBC allowing for the development of a wide array of new therapeutic options. This review aims to summarize the current evidence and ongoing clinical trials of new therapeutic options for the neoadjuvant treatment of TNBC patients.

Translational Implications of Dysregulated Pathways and MicroRNA Regulation in Quadruple-Negative Breast Cancer

Triple-negative breast cancers (HER2−, ER−, PR−) continue to present a unique treatment challenge and carry unfavorable prognoses. The elucidation of novel therapeutic targets has necessitated the re-evaluation of stratification approaches to best predict prognosis, treatment response and theranostic and prognostic markers. Androgen receptor expression and function have important implications on proliferation, tumor progression, immunity and molecular signaling in breast cancer. Accordingly, there has been increasing support for classification of androgen receptor-negative triple-negative breast cancer or quadruple-negative breast cancer (QNBC). QNBC has unique molecular, signaling and expression regulation profiles, particularly those affected by microRNA regulatory networks. MicroRNAs are now known to regulate AR-related targets and pathways that are dysregulated in QNBC, including immune checkpoint inhibitors (ICIs), SKP2, EN1, ACSL4 and EGFR. In this review, we explore and define the QNBC tumor subtype, its molecular and clinical distinctions from other subtypes, miRNA dysregulation and function in QNBC, and knowledge gaps in the field. Potential insights into clinical and translational implications of these dysregulated networks in QNBC are discussed.

Impact of Androgen Receptor Expression and the AR:ER Ratio on the Survival Outcomes in the Diverse Subgroups of Vietnamese Breast Cancer: A Single Institutional Retrospective Cohort Analysis

Background: The androgen receptor (AR) has recently emerged as a useful marker for the more favorable prognosis and better outcomes among women with estrogen receptor (ER) + ve breast cancer (BC) and the further refinement of BC subtype. Furthermore, AR expression in ER − ve tumors has a particular prognostic significance. Additionally, the ratio of nuclear AR to ER may critically have an influence on tumor biology and respond to endocrine therapy. Purpose: To define the AR expression and AR:ER ratio, and explored their correlation with the clinicopathological features, prognosis, and survival outcomes in the various subclasses of invasive BC. Methods: The current study was conducted on 522 BC patients who had surgical operations, without neoadjuvant chemotherapy by applying a retrospective cohort analysis. The clinicopathological characteristics were recorded. Immunohistochemical staining was performed on AR, ER, PR, HER2, and Ki67. Expression of AR was paired into different immunophenotypes for analysis with clinicopathological features and survival. All BC patients’ survival was analyzed using Kaplan–Meier and log-rank models. Results: The presence of AR was detected in 65.3%. Positive AR, the ratio of AR:ER<2, luminal androgen receptor (LAR) + and AR + HER2 + immunophenotypes were significantly associated with better prognostic features. AR:ER<2 was observed in the prolonged overall survival (OS) and disease-free survival (DFS) (87.9 and 86.2%, respectively) compared to AR:ER≥2 (25.0% in both) (P < .001). In contrast, in HR + ve BCs, the AR expression was not significantly correlated with survival. The multivariate model revealed that the ratio of nuclear AR to ER remained as an independent prognostic variable. Conclusion: The AR expression had a distinct OS and DFS. The AR:ER ratio is an independent indicator for predicting the OS and DFS of BC patients in both univariate and multivariate analyses.

Molecular Targets and Promising Therapeutics of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is one of the most heterogeneous diseases in solid tumors and has limited therapeutic options. Due to the lack of appropriate targetable markers, the mainstay therapeutic strategy for patients with TNBC has been chemotherapy for the last several decades. Indeed, TNBC tumors have no expression of estrogen receptor, progesterone receptor, or human epidermal growth factor receptor 2 (HER2); therefore, they do not respond to hormone therapy and HER2-targeted therapy. In this review paper, the molecular heterogeneities, possible therapeutic targets, and recently approved and upcoming drugs for TNBC will be summarized.

Ferroptosis: A Trusted Ally in Combating Drug Resistance in Cancer

Ferroptosis, which is an iron-dependent, non-apoptotic cell death mechanism, has recently been proposed as a novel approach in cancer treatment. Bearing distinctive features and its exclusive mechanism have put forward the potential therapeutic benefit of triggering this newly discovered form of cell death. Numerous studies have indicated that apoptotic pathways are often deactivated in resistant cells, leading to a failure in therapy. Hence, alternative strategies to promote cell death are required. Mounting evidence suggests that drug-resistant cancer cells are particularly sensitive to ferroptosis. Given that cancer cells consume a higher amount of iron than healthy ones, ferroptosis not only stands as an excellent alternative to trigger cell death and reverse drug-resistance, but also provides selectivity in therapy. This review focuses specifically on overcoming drug-resistance in cancer through activating ferroptotic pathways and brings together the relevant chemotherapeutics-based and nanotherapeutics-based studies to offer a perspective for researchers regarding the potential use of this mechanism in developing novel therapeutic strategies.

The role of androgens in women's health and wellbeing

Androgens in women, as well as in men, are intrinsic to maintenance of (i) reproductive competency, (ii) cardiac health, (iii) appropriate bone remodeling and mass retention, (iii) muscle tone and mass, and (iv) brain function, in part, through their mitigation of neurodegenerative disease effects. In recognition of the pluripotency of endogenous androgens, exogenous androgens, and selected congeners, have been prescribed off-label for several decades to treat low libido and sexual dysfunction in menopausal women, as well as, to improve physical performance. However, long-term safety and efficacy of androgen administration has yet to be fully elucidated. Side effects often observed include (i) hirsutism, (ii) acne, (iii) deepening of the voice, and (iv) weight gain but are associated most frequently with supra-physiological doses. By contrast, short-term clinical trials suggest that the use of low-dose testosterone therapy in women appears to be effective, safe and economical. There are, however, few clinical studies, which have focused on effects of androgen therapy on pre- and post-menopausal women; moreover, androgen mechanisms of action have not yet been thoroughly explained in these subjects. This review considers clinical effects of androgens on women's health in order to prevent chronic diseases and reduce cancer risk in gynecological tissues.

Imaging Androgen Receptors in Breast Cancer with 18F-fluoro-5α-dihydrotestosterone-PET: A Pilot Study

Most breast cancers express androgen receptors (AR). This prospective imaging sub-study explored imaging AR with ¹⁸F-fluoro-5α-dihydrotestosterone (FDHT)-PET in patients with metastatic breast cancer (MBC) receiving selective AR modulation (SARM) therapy (GTx-024, GTx, Inc). Methods: 11 post-menopausal women with estrogen receptor positive MBC underwent FDHT-PET/CT at baseline, 6, and 12 weeks after starting SARM therapy. Abnormal tumor FDHT uptake was quantified using maximum SUV (SUVmax). AR status was determined from tumor biopsy specimens. FDHT-SUVmax percent change between scans was calculated. Best overall response was categorized as clinical benefit (CB: non-progressive disease [PD]), or PD using RECIST 1.1. Results: Median baseline FDHT-SUVmax was 4.1 (range 1.4-5.9) for AR+ tumors versus 2.3 (range 1.5-3.2) for AR- tumors (p=0.22). Quantitative AR expression and baseline FDHT uptake were weakly correlated (Pearson rho=0.39, p=0.30). Seven participants with CB at 12 weeks tended to have larger declines in FDHT uptake compared to those with PD at both 6 (median decline, range: -26.8%, -42.9 to -14.1% vs. -3.7%, -31% to +29%, respectively, p=0.11) and 12 weeks (median decline, range: -35.7%, -69.5 to -7.7% vs. -20.1%, -26.6% to +56.5%, respectively, p=0.17) after starting GTx-024. Conclusion: This hypothesis-generating data suggests that FDHT-PET/CT is worth further study as an imaging biomarker for evaluating response of MBC to SARM therapy and reiterates the feasibility of including molecular imaging in multidisciplinary therapeutic trials.

The recent advances of PD-1 and PD-L1 checkpoint signaling inhibition for breast cancer immunotherapy

Over the past decade, there has been sustained research activity on programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) immune checkpoint inhibitors for breast cancer (BC) immunotherapy. Several clinical studies have demonstrated the anti-tumor efficacy of monotherapy drugs targeting PD-1 and PD-L1 checkpoint signaling in BC. Besides, the combination of anti-PD-1/PD-L1 agents with other inhibitors, including poly-adenosine diphosphate-ribose polymerase (PARP) inhibitors, vaccines, mitogen-activated protein kinase (MEK) inhibitors, and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) inhibitors are being investigated to improve drug efficacy. These trials have performed well and have shown better and more sustainable therapeutic responses. As follows, the purpose of this review is to discuss the recent advances in BC immunotherapy targeting the inhibition of PD-1/PD-L1 immune checkpoint signaling, when recommended as a monotherapy or in conjunction with other treatments. We look forward to providing new insights into the current state of BC research and the future direction of PD-1/PD-L1 immune checkpoint signaling.

Identification of the anti-breast cancer targets of triterpenoids in Liquidambaris Fructus and the hints for its traditional applications

BACKGROUND

Liquidambaris Fructus is the infructescences of Liquidambar formosana Hance and it has been used to treat some breast disease in Traditional Chinese Medicine. In the previous study we found the anti-breast cancer effect of triterpenoid in Liquidambaris Fructus. This study is a further investigation of the triterpenoids in Liquidambaris Fructus and aims to identify their anti-breast cancer targets, meanwhile, to estimate the rationality of the traditional applications of Liquidambaris Fructus.

METHODS

Triterpenoids in Liquidambaris Fructus were isolated and their structures were identified by NMR spectrums. Potential targets of these triterpenoids were predicted using a reverse pharmacophore mapping strategy. Associations between these targets and the therapeutic targets of breast cancer were analyzed by constructing protein-protein interaction network, and targets played important roles in the network were identified using Molecular Complex Detection method. Binding affinity between the targets and triterpenoids was studied using molecular docking method. Gene ontology enrichment analysis was conducted to reveal the biological process and signaling pathways that the identified targets were involved in.

RESULTS

Thirteen triterpenoids were identified and 6 of them were the first time isolated from Liquidambaris Fructus. Predicted ADME properties revealed a good druggability of these triterpenoids. We identified 18 protein targets which were closely related to breast cancer progression, especially triple-negative, basal-like or advanced stage breast cancers. The triterpenoids could bind with these targets as their inhibitors: hydrophobic skeleton is a favorable factor for them to stabilize at binding site and polar C17- or C3- substituent was necessary for binding. GO enrichment analysis indicated that inhibition of protein tyrosine kinases autophosphorylation might be the primary mechanism for the anti-breast cancer effect of the triterpenoids, and ErbB4 and EGFR were the most relevant targets.

CONCLUSIONS

The study revealed that triterpenoids from Liquidambaris Fructus might exert anti-breast cancer effect by directly inhibit multiple protein targets and signaling pathways, especially ErbB4 and EGFR and related pathways. This study also brings up another hint that the traditional applications of Liquidambaris Fructus on hypogalactia should be reassessed systematically because it might suppress rather than promote lactation by inhibiting the activity of ErbB4.

Androgen receptor expression inversely correlates with histological grade and N stage in ER+/PgRlow male breast cancer

PURPOSE

Androgen Receptor (AR) positivity is often displayed in breast cancer and especially in Male Breast Cancer (MBC), where it appears to be a heterogeneous feature, with its expression ranging between 38 and 81% of cases. Given the fact that circulating androgens represent the most important sex hormones in males and that breast carcinogenesis is characteristically subjected to hormonal mechanisms, our purpose was to investigate the clinicopathological significance of AR in MBC assessing if its expression could be associated with parameters of tumor aggressiveness.

METHODS

Clinical and pathological data were retrospectively reviewed for male patients with a diagnosis of invasive breast cancer. AR status was detected by immunohistochemistry on formalin-fixed, paraffin-embedded tumoral tissue sections. Correlations between AR expression and histopathological features were assessed using univariate and multiple comparisons where appropriate, assuming P values < 0.05 as statistically significant.

RESULTS

The study included 44 consecutive male patients. AR expression ranged between 10 and 98% and the majority of cases presented a moderate to high expression of this receptor. Adopting a 20% PgR cut-off, statistical analyses highlighted a different behavior of AR: in ER⁺/PgR^high group, it positively correlated with the other steroid receptors pointing out the importance of hormonal cross-talk: in ER⁺/PgR^low group, AR status inversely correlated with histological grade and lymph node status.

CONCLUSION

Hormonal factors reveal to play a crucial role in MBC carcinogenesis and progression. Intriguingly, in ER⁺/PgR^low tumors AR expression significantly correlates with lymph node status, hinting at a favorable biological role of AR in this tumor subgroup.

Distribution and characteristics of androgen receptor (AR) in breast cancer among women in Addis Ababa, Ethiopia: A cross sectional study

Evaluation of the role of androgen receptor (AR) in the biology of breast cancer is an emerging area of research. There are compelling evidences that AR expression may be used to further refine breast cancer molecular subtyping with prognostic and therapeutic implications. Many studies indicated co-expression of AR with the hormonal receptors in breast cancer has a favorable prognosis. AR is also investigated by many researchers as a potential therapeutic target in treatment of breast cancer. Studies on the frequency and distribution of AR in breast cancer among Africans is barely available. Given the heightened interest to understand its role in breast cancer, we determined AR expression and assessed its association with clinicopathological parameters among Ethiopian women. In this study, 112 newly diagnosed patient with invasive breast cancer at Tikur Anbessa Specialized Hospital were enrolled. Immunohistochemical assessment of AR, ER, PR, Ki67 and HER2 were performed using tissue microarrays (TMA) constructed from their primary tumor block. Out of the 112 participants, 91 (81%) were positive for AR expression and the remaining 21 participants (19%) were negative for AR expression. Expression of AR in ER+, HER2+ and TNBC cases were 93%, 83% and 48% respectively. Our study reveals AR is expressed in a significant number of breast cancers patients and this may indicate that breast cancers cases in Ethiopia have favorable prognosis and could benefit from progresses in AR targeted treatments. Since AR expression has important consequences on the prognosis and treatment of breast cancer, further studies with an increased number of participants is necessary to confirm our reports.

AR ubiquitination induced by the curcumin analog suppresses growth of temozolomide-resistant glioblastoma through disrupting GPX4-Mediated redox homeostasis

Drug resistance is the main obstacle in the improvement of chemotherapeutic efficacy in glioblastoma. Previously, we showed that dehydroepiandrosterone (DHEA), one kind of androgen/neurosteroid, potentiates glioblastoma to acquire resistance through attenuating DNA damage. Androgen receptor (AR) activated by DHEA or other types of androgen was reported to promote drug resistance in prostate cancer. However, in DHEA-enriched microenvironment, the role of AR in acquiring resistance of glioblastoma remains unknown. In this study, we found that AR expression is significantly correlated with poor prognosis, and AR obviously induced the resistance to temozolomide (TMZ) treatment. Herein, we observed that ALZ003, a curcumin analog, induces FBXL2-mediated AR ubiquitination, leading to degradation. Importantly, ALZ003 significantly inhibited the survival of TMZ-sensitive and -resistant glioblastoma in vitro and in vivo. The accumulation of reactive oxygen species (ROS), lipid peroxidation and suppression of glutathione peroxidase (GPX) 4, which are characteristics of ferroptosis, were observed in glioblastoma cell after treatment of ALZ003. Furthermore, overexpression of AR prevented ferroptosis in the presence of GPX4. To evaluate the therapeutic effect in vivo, we transplanted TMZ-sensitive or -resistant U87MG cells into mouse brain followed by intravenous administration with ALZ003. In addition to inhibiting the growth of glioblastoma, ALZ003 significantly extended the survival period of transplanted mice, and significantly decreased AR expression in the tumor area. Taken together, AR potentiates TMZ resistance for glioblastoma, and ALZ003-mediated AR ubiquitination might open a new insight into therapeutic strategy for TMZ resistant glioblastoma.

Efficacy and Safety of Targeting Androgen Receptor in Advanced Breast Cancer: A Systematic Review

Background::

Androgen receptor (AR) upstreams complex signaling pathways that regulate cell proliferation and contribute to breast tumorignensis. Several clinical trials were initiated to investigate the clinical relevance of targeting AR especially in hormone-receptor-negative breast cancer.

Methods::

The search was performed in PubMed and the meeting libraries of ASCO, ESMO, SABCS, ImpakT congresses from January 2005 to July 2017. The following key words were used: Breast cancer, Androgen receptor, androgen agonist/antagonist, Flutamide, Abiraterone, Bicalutamide, Enzalutamide, Enobosarm, selective androgen receptor modulator.

Results::

Screening of title/abstracts yielded a total of 20 relevant results. Of those, twelve studies were found eligible: eleven clinical trials along with one case report. Response rates ranged from 0 to 12% while clinical benefit rates reached up to 35% in 2 studies (with enzalutamide and enobosarm). Progression-free survival ranged from 2.8 to 4.5 months. The most widely used cutoff for AR expression was 10%. High expression of AR was associated with more clinical benefit. Regarding safety, anti-androgens were generally well tolerated with hot flushes, elevated transaminases and fatigue being the most commonly reported across all agents.

Conclusion::

Androgen receptor pathway targeting in advanced breast cancer remains a valid option with reasonable clinical benefit in non-selected patients. Future studies are needed to define an AR addicted cohort with better responses and outcome.

Androgen Receptors in Resected Ductal Carcinoma In Situ of Breast: Novel Insights With Possible Implications for Testing and Targeted Endocrine Chemoprevention Trials

Mammary ductal carcinoma in situ (DCIS) is classically treated by combinations of excision, radiation, and endocrine therapy, based upon the specific needs of individual patients. Estrogen receptor (ER) status is generally assessed by immunohistochemistry (IHC) in newly diagnosed cases of DCIS, and endocrine therapy in this setting is thought to be chemopreventive. The potential impact of androgens on mammary carcinogenesis has been studied in recent years, and several authors have proposed androgen receptor (AR) IHC testing and targeted antiandrogenic therapy in patients with locally advanced or metastatic triple-negative invasive breast cancer (ie, negative for ER and progesterone receptor and HER-2). Very little has been published on AR in DCIS. We report results of AR IHC on archival tissue blocks from 221 adult female patients, each of whom underwent definitive breast resection of DCIS. Of the 221 cases, 72 (33%) were shown to express AR in their DCIS at or above the 10% threshold often used for invasive carcinoma. AR expression was seen in all grades of DCIS. Of the 72 positive AR cases, 21 (29%) were ER negative, corresponding to 10% (21/221) of all patients. The majority of the AR-positive cases were high grade, and the most common histologic subtype in this subset was a solid growth pattern with apocrine features. Early data from clinical trials evaluating AR antagonists in invasive/metastatic triple-negative breast cancer suggest that some patients may benefit from androgen blockade. IHC testing and potential clinical trials of AR antagonists for chemoprevention in patients with AR-positive and ER-negative DCIS could be considered.

Androgen receptor: A promising therapeutic target in breast cancer

Breast cancer (BCa) is the second most common cancer worldwide and the most prevalent cancer in women. The majority of BCa cases are positive (+) for the estrogen receptor (ER⁺, 80%) and progesterone receptor (PR⁺, 65%). Estrogen and progesterone hormones are known to be involved in cancer progression, and thus hormonal deprivation is used as an effective treatment for ER⁺PR⁺ BCa subtypes. However, some ER⁺PR⁺ BCa patients develop resistance to such therapies. Meanwhile, chemotherapy is the only available treatment for ER^-PR^- BCa tumors. Another hormone receptor known as the androgen receptor (AR) has also been found to be widely expressed in human breast carcinomas. However, the mechanisms of AR and its endogenous androgen ligands is not well-understood in BCa and its biological role in this hormone-related disease remains unclear. In this review, we aim to address the importance of the AR in BCa diagnosis and prognosis, current AR-targeting approaches in BCa, and the potential for AR-downstream molecules to serve as therapeutic targets.

Selective Androgen Receptor Modulators: Current Knowledge and Clinical Applications

INTRODUCTION

Selective androgen receptor modulators (SARMs) differentially bind to androgen receptors depending on each SARM's chemical structure. As a result, SARMs result in anabolic cellular activity while avoiding many of the side effects of currently available anabolic steroids. SARMs have been studied in the treatment of breast cancer and cachexia and have also been used as performance-enhancing agents. Here, we evaluate and summarize the current literature on SARMs.

AIM

To present the background, mechanisms, current and potential clinical applications, as well as risks and benefits of SARMs.

METHODS

A literature review was performed in MEDLINE using the terms selective androgen receptor modulator, hypogonadism, cachexia, breast cancer, benign prostatic hyperplasia, libido, and lean muscle mass. Both basic research and clinical studies were included.

MAIN OUTCOME MEASURE

To complete a review of peer-reviewed literature.

RESULTS

Although there are currently no U.S. Food and Drug Agency-approved indications for SARMs, investigators are exploring the potential uses for these compounds. Basic research has focused on the pharmacokinetics and pharmacodynamics of these agents, demonstrating good availability with a paucity of drug interactions. Early clinical studies have demonstrated potential uses for SARMs in the treatment of cancer-related cachexia, benign prostatic hyperplasia (BPH), hypogonadism, and breast cancer, with positive results.

CONCLUSION

SARMs have numerous possible clinical applications, with promise for the safe use in the treatment of cachexia, BPH, hypogonadism, breast cancer, and prostate cancer. Solomon ZJ, Mirabal JR, Mazur DJ, et al. Selective Androgen Receptor Modulators: Current Knowledge and Clinical Applications. Sex Med Rev 2019;7:84-94.

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.

Androgen receptor in triple negative breast cancer: A potential target for the targetless subtype

Triple negative breast cancer (TNBC) represents the 15-20% of all breast cancers (BC) and is characterized by a very aggressive behavior. Recent data suggest that TNBC is not a single disease, but it is rather an umbrella for different ontology-profiles such as basal like 1 and 2, mesenchymal, and the luminal androgen receptor (LAR). The LAR subtype is characterized by the expression of the Androgen Receptor (AR) and its downstream effects. Notwithstanding the role of the AR in several signaling pathways, its impact on a biological and clinical standpoint is still controversial. The LAR subtype has been associated with better prognosis, less chemotherapy responsiveness and lower pathologic complete response after neoadjuvant treatment. Clinical evidence suggests a role for anti-androgen therapies such as bicalutamide, enzalutamide and abiraterone, offering an interesting chemo-free alternative for chemo-unresponsive patients, and therefore potentially shifting current treatment strategies.

Possible roles for glucocorticoid signalling in breast cancer

Our understanding of breast cancer biology, and our ability to manipulate breast cancers have grown exponentially in the last 20 years. Much of that expansion has focused on the roles of steroids in driving these neoplasms. Initially this research focused on estrogens and progesterone receptors, and more recently on androgen actions in breast cancers. This review aims to make the case for glucocorticoids as the next essential steroid subclass that contributes significantly to our understanding of steroidogenic regulation of these neoplasms. Glucocorticoids have the potential to play multiple roles in the regulation of breast cancers including their control of cellular differentiation, apoptosis and proliferation. Beyond this they also act as a master integrator of organ homeostats in relation to such as circadian rhythms and stress responses. Therefore a better understanding of glucocorticoids and breast cancer could help to explain some of the epidemiological links between circadian disruption and/or stress and breast cancer development. Finally glucocorticoids are currently used during chemotherapeutic treatment in breast cancer therapy and yet results of various studies suggest that this may have an adverse impact on treatment success. This review aims to summarise the current evidence for glucocorticoids as actors in breast cancer and then suggest future essential approaches in order to determine the roles of glucocorticoids in this disease.

Development of selective androgen receptor modulators (SARMs)

The Androgen Receptor (AR), a member of the steroid hormone receptor family, plays important roles in the physiology and pathology of diverse tissues. AR ligands, which include circulating testosterone and locally synthesized dihydrotestosterone, bind to and activate the AR to elicit their effects. Ubiquitous expression of the AR, metabolism and cross reactivity with other receptors limit broad therapeutic utilization of steroidal androgens. However, the discovery of selective androgen receptor modulators (SARMs) and other tissue-selective nuclear hormone receptor modulators that activate their cognate receptors in a tissue-selective manner provides an opportunity to promote the beneficial effects of androgens and other hormones in target tissues with greatly reduced unwanted side-effects. In the last two decades, significant resources have been dedicated to the discovery and biological characterization of SARMs in an effort to harness the untapped potential of the AR. SARMs have been proposed as treatments of choice for various diseases, including muscle-wasting, breast cancer, and osteoporosis. This review provides insight into the evolution of SARMs from proof-of-concept agents to the cusp of therapeutic use in less than two decades, while covering contemporary views of their mechanisms of action and therapeutic benefits.

Estrogen and androgen-converting enzymes 17β-hydroxysteroid dehydrogenase and their involvement in cancer: with a special focus on 17β-hydroxysteroid dehydrogenase type 1, 2, and breast cancer

Sex steroid hormones such as estrogens and androgens are involved in the development and differentiation of the breast tissue. The activity and concentration of sex steroids is determined by the availability from the circulation, and on local conversion. This conversion is primarily mediated by aromatase, steroid sulfatase, and 17β-hydroxysteroid dehydrogenases. In postmenopausal women, this is the primary source of estrogens in the breast. Up to 70-80% of all breast cancers express the estrogen receptor-α, responsible for promoting the growth of the tissue. Further, 60-80% express the androgen receptor, which has been shown to have tissue protective effects in estrogen receptor positive breast cancer, and a more ambiguous response in estrogen receptor negative breast cancers. In this review, we summarize the function and clinical relevance in cancer for 17β-hydroxysteroid dehydrogenases 1, which facilitates the reduction of estrone to estradiol, dehydroepiandrosterone to androstendiol and dihydrotestosterone to 3α- and 3β-diol as well as 17β-hydroxysteroid dehydrogenases 2 which mediates the oxidation of estradiol to estrone, testosterone to androstenedione and androstendiol to dehydroepiandrosterone. The expression of 17β-hydroxysteroid dehydrogenases 1 and 2 alone and in combination has been shown to predict patient outcome, and inhibition of 17β-hydroxysteroid dehydrogenases 1 has been proposed to be a prime candidate for inhibition in patients who develop aromatase inhibitor resistance or in combination with aromatase inhibitors as a first line treatment. Here we review the status of inhibitors against 17β-hydroxysteroid dehydrogenases 1. In addition, we review the involvement of 17β-hydroxysteroid dehydrogenases 4, 5, 7, and 14 in breast cancer.

AR Signaling in Human Malignancies: Prostate Cancer and Beyond

The notion that androgens and androgen receptor (AR) signaling are the hallmarks of prostate cancer oncogenesis and disease progression is generally well accepted. What is more poorly understood is the role of AR signaling in other human malignancies. This special issue of Cancers initially reviews the role of AR in advanced prostate cancer, and then explores the potential importance of AR signaling in other epithelial malignancies. The first few articles focus on the use of novel AR-targeting therapies in castration-resistant prostate cancer and the mechanisms of resistance to novel antiandrogens, and they also outline the interaction between AR and other cellular pathways, including PI3 kinase signaling, transcriptional regulation, angiogenesis, stromal factors, Wnt signaling, and epigenetic regulation in prostate cancer. The next several articles review the possible role of androgens and AR signaling in breast cancer, bladder cancer, salivary gland cancer, and hepatocellular carcinoma, as well as the potential treatment implications of using antiandrogen therapies in these non-prostatic malignancies.

The Androgen Receptor in Breast Cancer

Breast cancer (BC) is a hormone-related tumor. Despite the progress in BC therapy, this disease still remains the most common cancer amongst women around the world. This is likely due to the amazing BC heterogeneity. Accumulating evidence suggests a role for androgen signaling in BC. Nevertheless, a precise understanding of the mechanism of androgen action in this disease remains a challenging puzzle. Androgen receptor (AR) is often expressed in BC and several studies suggest that its role depends on the tumor microenvironment as well as the relative levels of circulating estrogens and androgens. However, the AR function in BC is still conflicting. Although AR expression is often associated with a favorable prognosis in EREstradiol Receptorα-positive (ERα +) BC, many findings suggest that, in some instances, high levels of AR can contribute to the therapy-resistance. Again, in ERα negative BC (ERα -), AR is mainly expressed in tumors with apocrine differentiation and a lower Nottingham grade. Moreover, AR stimulates cellular proliferation in triple negative breast cancer (ERα -, PgR -, and HER-2-Neu -). This finding is substantiated by the observation that high levels of circulating androgens are associated with an increased risk of developing BC in post-menopausal woman. Treatment of ERα- BC with AR antagonists, such as bicalutamide or enzalutamide, reduces, indeed, the tumor growth. In this review, we will analyze the putative role of AR in BC. Emerging therapies based on the use of new agonists or antagonists or inhibitors will be here discussed.

Androgen receptor in estrogen receptor positive breast cancer: Beyond expression

In recent years, new therapeutic approaches have reshaped the overall strategy of breast cancer (BC) treatment and have markedly improved patient survival. This is, in part, due to novel therapies for estrogen receptor (ER)-positive BC. Unfortunately, many patients present de novo resistance to these therapies or develop an acquired resistance over time. Therefore, research is now focused on discovering new molecular targets to overcome these resistances. Interestingly, preclinical and clinical studies have shown a critical role for the cross-talk between androgen receptor (AR) and ER in luminal-like BC. AR is expressed in >60% of BC and in up to 90% of ERα-positive tumors. Multiple studies suggest that AR is associated with a favorable prognosis. However, AR overexpression and, in particular, the high AR:ER ratio, seem to be involved in resistance to hormonal treatment. In this setting, a group of BCs could benefit from AR-inhibitors; nevertheless, some ER-positive BC patients do not seem to benefit from this strategy. Therefore, it is crucial to identify biomarkers that would enable the selection of patients who might benefit from combination treatment with ER and AR inhibitors.

Effects of cytokines derived from cancer-associated fibroblasts on androgen synthetic enzymes in estrogen receptor-negative breast carcinoma

PURPOSE

The tumor microenvironment plays pivotal roles in promotion of many malignancies. Cancer-associated fibroblasts (CAFs) have been well-known to promote proliferation, angiogenesis, and metastasis but mechanistic understanding of tumor-stroma interactions is not yet complete. Recently, estrogen synthetic enzymes were reported to be upregulated by co-culture with stromal cells in ER positive breast carcinoma (BC) but effects of co-culture on androgen metabolism have not been extensively examined. Therefore, we evaluated roles of CAFs on androgen metabolism in ER-negative AR-positive BC through co-culture with CAFs.

METHODS

Concentrations of steroid hormone in supernatant of co-culture of MDA-MB-453 and primary CAFs were measured using GC-MS. Cytokines derived from CAFs were determined using Cytokine Array. Expressions of androgen synthetic enzymes were confirmed using RT-PCR and Western blotting. Correlations between CAFs and androgen synthetic enzymes were analyzed using triple-negative BC (TNBC) patient tissues by immunohistochemistry.

RESULTS

CAFs were demonstrated to increase expressions and activities of 17βHSD2, 17βHSD5, and 5α-Reductase1. IL-6 and HGF that were selected as potential paracrine mediators using cytokine array induced 17βHSD2, 17βHSD5, and 5α-Reductase1 expression. Underlying mechanisms of IL-6 paracrine regulation of 17βHSD2 and 17βHSD5 could be partially dependent on phosphorylated STAT3, while phosphorylated ERK could be involved in HGF-mediated 5α-Reductase1 induction. α-SMA status was also demonstrated to be significantly correlated with 17βHSD2 and 17βHSD5 status in TNBC tissues, especially AR-positive cases.

CONCLUSIONS

Results of our present study suggest that both IL-6 and HGF derived from CAFs could contribute to the intratumoral androgen metabolism in ER-negative BC patients.

Anti-tumor efficacy of new 7α-substituted androstanes as aromatase inhibitors in hormone-sensitive and resistant breast cancer cells

The majority of breast cancer cases are estrogen receptor positive (ER⁺). Although, third-generation aromatase inhibitors (AIs) are used as first-line treatment in post-menopausal women, they cause endocrine resistance and bone loss, which limits their success. Therefore, there is a demand to discover new potent molecules, with less toxicity that can circumvent these drawbacks. Our group has previously demonstrated that new 7α-substituted steroidal molecules, 7α-(2ξ,3ξ-epoxypropyl)androsta-1,4-diene-3,17-dione (3), 7α-allylandrost-4-ene-3,17-dione (6), 7α-allylandrost-4-en-17-one (9), 7α-allyl-3-oxoandrosta-1,4-dien-17β-ol (10) and 7α-allylandrosta-1,4-diene-3,17-dione (12) are potent AIs in placental microsomes. In this work, it was investigated their anti-aromatase activity and in vitro effects in sensitive and resistant breast cancer cells. All the steroids efficiently inhibit aromatase in breast cancer cells, allowing to establish new structure-activity relationships for this class of compounds. Moreover, the new AIs can inhibit breast cancer cell growth, by causing cell cycle arrest and apoptosis. The effects of AIs 3 and 12 on sensitive cells were dependent on aromatase inhibition and androgen receptor (AR), while for AI 9 and AI 10 were AR- and ER-dependent, respectively. In addition, it was shown that all the AIs can sensitize resistant cancer cells being their behavior similar to the sensitive cells. In summary, this study contributes to the understanding of the structural modifications in steroidal scaffold that are translated into better aromatase inhibition and anti-tumor properties, providing important information for the rational design/synthesis of more effective AIs. In addition, allowed the discovery of new potent 7α-substituted androstane molecules to inhibit tumor growth and prevent endocrine resistance.

DNA Mutations May Not Be the Cause of Cancer

Cancer is the most challenging disease of our time with increasing numbers of new cases each year, worldwide. Great achievements have been reached in cancer research through deep sequencing which helped define druggable targets. However, the still-evolving targeted therapy suffers resistance suggesting that DNA mutations considered as drivers may not have a role in tumor initiation. The present work discusses the role of DNA mutations as drivers and passengers in cancer initiation and development. First, it is important to discern the role of these DNA mutations as initiating events causing cancer or as contributors crucial for the development of a tumor once it has initiated. Second, breast cancer shown here illustrates how identification of DNA mutations in cancerous cells has influenced our approach for anti-cancer drug design. The cancer trilogy we have reached and described as: initial drug; resistance/recurrence; drug/treatment combinations, calls for a paradigm shift. To design more effective cancer drugs with durable and positive outcome, future cancer research needs to move beyond the sequencing era and explore changes which are taking place in cancer cells at levels other than the DNA. Evolutionary constraints may be acting as a barrier to preserve the human species from being transformed and, for that matter, all multi-cellular species which can incur cancer. Furthermore, mutations in the DNA do occur and for a multitude of reasons but without necessarily causing cancer. New directions will draw themselves when more focus is given to the event responsible for the switch of a cell from normalcy to malignancy. Until then, targeted therapy will certainly continue to improve the outcome of patients; however, it is unlikely to eradicate breast cancer depicted here.

A comparison of the molecular subtypes of triple-negative breast cancer among non-Asian and Taiwanese women

Background

“Precision medicine” is a concept that by utilizing modern molecular diagnostics, an effective therapy is accurately applied for each cancer patient to improve their survival rates. The treatment of triple-negative breast cancer (TNBC) remains a challenging issue. The aim of this study was to compare the molecular subtypes of triple-negative breast cancer (TNBC) between Taiwanese and Non-Asian women.

Methods

GEO Datasets for non-Asian (12 groups, n = 1450) and Taiwanese (3 groups, n = 465) breast cancer, including 617 TNBC, were acquired, normalized and cluster analyzed. Then, using TNBC cell lines of different subtypes, namely, MDA-MB-468 (basal-like1, BL1), MDA-MB-231 (mesenchymal stem like, MSL), BT-549 (mesenchymal, M), MDA-MB-453 (luminal androgen receptor, LAR), and DU4475 (immunomodulatory, IM), real-time PCR in triplicate for 47 genes signatures were performed to validate the specificity of these subtypes.

Results

The results showed that the percentage of TNBC subtypes in non-Asian women, namely, BL1, BL2, IM, M, MSL, and LAR was 13.56, 8.91, 16.80, 20.45, 8.30, and 11.13%, respectively. When data from Taiwanese were normalized and clustered, five TNBC subtypes, namely, BL (8.94%), IM (13.82%), M (22.76%), MSL (30.89%), and LAR (23.58%), were classified. Real-time PCR validated the specificity of these subtypes. Besides, the presence of interaction between IM- and MSL-subtypes suggests the involvement of tumor microenvironment in TNBC subtype classification.

Conclusion

Our data suggested that there exist different presentations between non-Asian and Taiwanese TNBC subtypes, which provides important information when selection of therapeutic targets or designs for clinical trials for TNBC patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s10549-017-4195-7) contains supplementary material, which is available to authorized users.

Androgen Receptor Signaling in Salivary Gland Cancer

Salivary gland cancers comprise a small subset of human malignancies, and are classified into multiple subtypes that exhibit diverse histology, molecular biology and clinical presentation. Local disease is potentially curable with surgery, which may be combined with adjuvant radiotherapy. However, metastatic or unresectable tumors rarely respond to chemotherapy and carry a poorer prognosis. Recent molecular studies have shown evidence of androgen receptor signaling in several types of salivary gland cancer, mainly salivary duct carcinoma. Successful treatment with anti-androgen therapy in other androgen receptor-positive malignancies such as prostate and breast cancer has inspired researchers to investigate this treatment in salivary gland cancer as well. In this review, we describe the prevalence, biology, and therapeutic implications of androgen receptor signaling in salivary gland cancer.

Expression and Clinical Significance of Androgen Receptor in Triple-Negative Breast Cancer

BACKGROUND

Triple-negative breast cancer (TNBC) has a poor prognosis because of frequent recurrence. Androgen receptor (AR) is involved in the pathogenesis of breast cancer, but its role is not clearly defined. The aim of this study was to explore the expression of AR and its relationship with clinicopathologic features in TNBC.

METHODS

This study investigated 1036 cases of sporadic invasive breast carcinoma. Immunohistochemical assays were performed to determine the expression of AR in 190 TNBC samples. The relationships between AR expression and clinicopathologic data and prognosis were analyzed.

RESULTS

In 190 TNBC cases, the prognosis of AR-positive patients was significantly better (p = 0.019, log-rank) than AR-negative patients, and in multivariate analysis, AR expression was an independent indicator of good prognosis (p = 0.039, hazard ratio = 0.36). In patients with disease relapse, AR positivity was significantly correlated with better prognosis (p = 0.034, log-rank).

CONCLUSIONS

AR expression may be useful as a subclassification marker for prognosis in TNBC.