Expression of androgen receptors in primary breast cancer

C/EBPβ increases tumor aggressiveness by enhancing KIFC1 expression in androgen receptor negative triple negative breast cancer

Quadruple-negative breast cancers (also known as AR-triple negative (TN) BC) lack the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and androgen receptor (AR). AR-TNBC exhibits aggressive characteristics and a poor prognosis. Because of the lack of expression of therapeutic targets, limited therapeutic options exist for patients with AR-TNBC. Hence, new therapeutic targets and risk-predictive biomarkers are required for patients with AR-TNBC. In this study, we investigated the role of kinesin-like protein 1 (KIFC1) in AR-TNBC. We found that C/EBPβ binds to the KIFC1 promoter and induces its expression in the AR-TNBC cells. Notably, AR status was negatively correlated with KIFC1 levels. We also found that AR transcriptionally repressed the transcription factor C/EBPβ, which regulates the expression of KIFC1. The lack of AR expression in AR-TNBC led to C/EBPβ upregulation, thereby enhancing KIFC1 expression. Moreover, upregulation of KIFC1 in AR-TNBC increased cancer cell proliferation and promoted epithelial-mesenchymal transition (EMT), contributing to the aggressive characteristics of AR-TNBC. Inhibiting KIFC1 using the small molecule inhibitor CW069 significantly reduced tumor volume in mice bearing AR-TNBC xenografts, but not in those with triple-negative breast tumors. These data suggest that upregulation of C/EBPβ and KIFC1 contributes to the aggressive characteristics and poor prognosis of AR-TNBC, providing strong evidence that targeting KIFC1 using kinesin inhibitors could be a viable therapeutic approach for patients with AR-TNBC.

Association of Androgen Receptor Expression With Tumor Immune Landscape and Treatment Outcomes of Patients With Breast Cancer

PURPOSE

Although estrogen receptor is well studied in breast cancer (BC), the role of androgen receptor (AR) in prognosis and therapy response is less understood. Here, we characterized the clinicopathologic and molecular features of AR gene expression in BC subtypes.

METHODS

Ten thousand seven hundred twenty-eight BC samples were tested by next-generation DNA sequencing, whole-transcriptome sequencing, and immunohistochemistry at Caris Life Sciences (Phoenix, AZ). Tumors with AR-high and AR-low RNA expression were stratified by top and bottom quartiles, respectively. Treatment-associated survival was obtained from insurance claims and calculated from treatment start to last contact using Kaplan-Meier estimates. Statistical significance was determined by chi-square and Mann-Whitney U test with P values adjusted for multiple comparisons (q < .05).

RESULTS

AR-low was associated with basal-like tumors. AR-high tumors were associated with increased mutation rates in several genes-namely PIK3CA and CDH1-across all subtypes, while other associations such as RB1 and MAP3K1 were subtype-dependent. The immune landscape was differentially affected by AR expression in each subtype, but these differences did not correspond to differential responses to immune checkpoint blockade. Patients with AR-high tumors had a longer therapy response for most subtypes, but those with AR-high tumors that were human epidermal growth factor receptor 2-enriched and luminal B trended toward worse chemotherapy or hormone therapy response, respectively.

CONCLUSION

Our data suggest a unique molecular profile of AR-high BC that is subtype-specific and generally associated with improved outcomes. Exploration of specific mutations and immune-oncology markers associated with AR-high may aid in molecularly selected clinical trial design for patients with advanced BC.

Hormone Signaling in Breast Development and Cancer

Hormones control normal breast development and function. They also impinge on breast cancer (BC) development and disease progression in direct and indirect ways. The major ovarian hormones, estrogens and progesterone, have long been established as key regulators of mammary gland development in rodents and linked to human disease. However, their roles have been difficult to disentangle because they act on multiple tissues and can act directly and indirectly on different cell types in the breast, and their receptors interact at different levels within the target cell. Estrogens are well-recognized drivers of estrogen receptor-positive (ER+) breast cancers, and the ER is successfully targeted in ER+ disease. The role of progesterone receptor (PR) as a potential target to be activated or inhibited is debated, and androgen receptor (AR) signaling has emerged as a potentially interesting pathway to target on the stage.In this chapter, we discuss hormone signaling in normal breast development and in cancer, with a specific focus on the key sex hormones: estrogen, progesterone, and testosterone. We will highlight the complexities of endocrine control mechanisms at the organismal, tissue, cellular, and molecular levels. As we delve into the mechanisms of action of hormone receptors, their interplay and their context-dependent roles in breast cancer will be discussed. Drawing insights from new preclinical models, we will describe the lessons learned and the current challenges in understanding hormone action in breast cancer.

Analyzing Androgen Receptor Expression in Breast Cancer: Insights into Histopathological Parameters and Hormone Receptor Status Among Indian Women

Breast cancer, an exceptionally hormone-dependent tumor, exhibits a diverse clinical profile. Its therapeutic categorization relies on the expression of key receptors, namely, estrogen receptor (ER), progesterone receptor (PR), and Her2neu. The androgen receptor (AR), a member of the nuclear receptor superfamily, is a biomarker gaining attention in breast cancer research, particularly for triple-negative breast cancers. We conducted an analysis of AR expression in 113 primary breast cancer cases, using a cutoff criterion of ≥ 10% tumor cell positivity. ER, PR, and Her2neu statuses were determined based on the 2023 ASCO-CAP criteria. AR expression was then correlated with various clinicopathological factors, including age, menopausal status, centricity, histological type, grade, tumor size, nodal status, lymphovascular and perineural invasion, and ER, PR, and HER2neu statuses. Among the 113 cases, 57 (50.4%) showed positive AR expression. No statistically significant associations were found between AR expression and age, menopausal status, histological type, histological grade, nodal status, or ER and PR expression. Notably, all multicentric tumors (n = 7, 100%) were AR negative. AR expression was linked to smaller tumor sizes. Positive AR cases exhibited an association with Her2neu overexpression, particularly in ER and PR-negative tumors. Of note, 35% of triple-negative tumors displayed AR positivity. AR emerges as a promising marker in breast cancers, particularly in triple-negative cases. Larger-scale studies are warranted to comprehensively assess the relationship between AR expression and histopathological parameters, as well as other immunohistochemical markers.

Correlation of Androgen Receptor Expression With Ki67 Proliferative Index and Other Clinicopathological Characteristics in Invasive Mammary Carcinomas

Introduction The clinical importance of androgen receptor (AR) status in breast cancer is uncertain. The existing knowledge regarding the association of androgen receptor expression with clinicopathological factors of breast cancer is also limited. The main aim of this study is to evaluate the AR expression in breast cancer and to correlate it with the Ki67 proliferative index and other clinicopathological prognostic factors. Methods The expression of AR was evaluated in 192 invasive mammary carcinoma cases and the expression patterns were correlated with various clinicopathological prognostic factors such as age, tumor size, pathological primary tumor (pT) stage, nodal status, histological grade, estrogen receptor (ER) expression, progesterone receptor (PgR) expression, human epidermal growth factor receptor 2 (Her2) status, molecular subtype, and Ki67 labeling index. Immunohistochemistry was performed to assess AR, ER, PgR, Her2, and Ki67 expression. The clinicopathological data required for the analysis were obtained from the laboratory information system. Results Out of the 192 breast carcinoma cases, 139 (72.4%) showed AR-positive expression. The average age of the AR-positive cases was slightly higher than the AR-negative cases. AR-positive tumors tended to have a lower histological grade and positive ER and PgR expression. The expression of AR did not correlate with tumor size, pT stage, nodal status, Her2 status, and Ki67 labeling index. Conclusion The expression of AR is noted in a significant proportion of breast carcinoma cases. AR expression may be related to good prognostic factors such as ER expression, PgR expression, and lower histologic grade. We also observed that AR expression did not have any association with the Ki67 proliferative index.

Incidence and Prognostic Significance of Androgen Receptors (AR) in Indian Triple-Negative Breast Cancer (TNBC)

Molecular sub-characterization of triple-negative breast cancer (TNBC) has great therapeutic and possibly prognostic implications. The primary aim of this study was to investigate the incidence of luminal androgen receptor (LAR) subtype of TNBC and secondary aims were sub-categorization and clinico-pathologic correlation of LAR breast cancers. Retrospective study (January 2008 and 31st of December 2018) consisting of 157 TNBC patients. Androgen receptor (AR) expression was measured by immunohistochemical analysis. One percent cutoff was set as a positive expression. Sub-categorization was done on the basis of EGFR (> 15% of tumor cells) and Ki-67 expression (low- < 11%, intermediate- 11-20%, and high- > 21%). AR expression was correlated with various clinico-pathologic features and outcomes of the patients. The incidence of AR expression in TNBC was 24.8%. Considering different thresholds of > 5%, > 10%, and > 20% immunostaining, the incidence of AR positivity was 18.4, 15.2, and 11.5% respectively. The incidence of Ki-67 (p = 0.89) and EGFR (p = 0.643) expression did not differ significantly in AR-positive and -negative TNBC. Based on EGFR expression 19, 67 and 14% patients were categorized as low, intermediate, and high risk respectively. Low-risk (p ≤ 0.001) and low-grade (p = 0.014) tumors were more likely to have > 10% AR expression. Clinico-pathological profile, response to neoadjuvant chemotherapy, disease-free survival (p = 0.458), and overall survival (p = 0.806) did not significantly differ between AR expressing and negative TNBC. On multivariate analysis, only tumor staging was a significant predictor of survival (p = 0.012) and AR expression of > 10% revealed a trend towards improved survival (p = 0.07). When considering only AR-positive TNBC, AR expression of > 10% (p = 0.038), distant metastases (p = 0.003), and EGFR status (p = 0.024) were significantly associated with survival. AR expression does not seem to very strongly correlate with prognosis in TNBC and further studies could focus more on its predictive role in deciding anti-androgen therapy.

Triple-negative breast cancer: from classical clinicopathological features to androgen receptor profile

Triple-negative breast cancer (BC) represents an extensively analyzed entity to establish the overall framework of clinicopathological characteristics, with an impact on defining prognostic and predictive factors. The relationship between triple-negative BC and androgen receptor (AR) is far from being clarified. We aimed to evaluate the classical clinicopathological spectrum that characterized a triple-negative BC, focusing on AR expression. The study group comprised 124 cases of triple-negative BC. The main clinicopathological parameters were extracted from medical records. The immunohistochemical (IHC) exam was run using the following antibodies: anti-estrogen receptor (ER), anti-progesterone receptor (PR), anti-human epidermal growth factor receptor (HER2∕neu), anti-Ki67 and anti-AR. AR immunoexpression was assessed as absent (completely negative) or present (unrelated to percentages and intensity). Data were statistically analyzed. AR expression was positive in 78 (63%) cases and negative in 46 (37%) cases. Among the study group, 28 cases exhibited an AR percentage ranging from 1% to 10%, 15 cases showed a percentage between 11% and 50%, while 12 cases had AR values between 51% and 75% and 23 cases fell within the AR range of 76% to 100%. No significant differences between AR immunoexpression (negative versus positive), clinicopathological characteristics and survival parameters were found. Statistically significant differences were registered between histological type, tumor stage, distant metastasis, tumor-infiltrating lymphocytes (TILs), treatment and residual cancer burden (RCB), and survival parameters. Thus, our results sustain that AR does not affect the biological behavior of triple-negative BC.

Determination of the androgen receptor status of disseminated tumor cells in primary breast cancer patients

PURPOSE

Androgen receptor (AR) can serve as a new therapeutic target since it was shown to play a proliferative role in several breast cancer (BC) subtypes. Moreover, AR positivity has been suggested to reflect the metastatic potential of tumor cells in some BC subtypes. The aim of this study was to determine the AR expression on disseminated tumor cells (DTCs) as a surrogate marker of minimal residual disease (MRD) and potential precursor of metastasis in early BC.

METHODS

Bone marrow (BM) aspirates from 62 DTC-positive early BC patients were included into this study and analyzed by immunofluorescence staining for the presence of AR-positive DTCs. CK-positive, CD45-negative cells containing an intact nucleus (DAPI positive) were identified as DTCs. AR expression of the primary tumor (PT) was assessed by immunohistochemistry on formalin-fixed, paraffin-embedded (FFPE) tumor sections from core biopsies and surgical specimens.

RESULTS

AR status of DTCs could be determined in 21 patients. We detected AR-positive DTCs in nine samples (43%). AR expression of DTCs and corresponding PT showed a concordance rate of 33%. The DTC-AR status did not correlate with clinicopathological factors, nor did we observe a significant correlation between the AR status of the PT and other established prognostic factors for BC.

CONCLUSION

AR-positive DTCs can be detected in BM of early BC patients with a marked discordance of the AR status between DTCs and corresponding PTs. The clinical significance of these findings needs further investigation.

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.

TRPS1 and GATA3 Expression in Invasive Breast Carcinoma With Apocrine Differentiation

CONTEXT.—

The recently identified immunohistochemical marker TRPS1 is highly sensitive and specific for invasive breast carcinoma, especially triple-negative breast carcinoma. However, TRPS1 expression in special morphologic subtypes of breast cancer is unclear.

OBJECTIVE.—

To investigate the expression of TRPS1 in invasive breast cancer with apocrine differentiation, in comparison to the expression of GATA3.

DESIGN.—

A total of 52 invasive breast carcinomas with apocrine differentiation, comprising 41 triple-negative breast carcinomas and 11 estrogen receptor (ER) and progesterone receptor (PR)-negative, human epidermal growth factor receptor 2 (HER2)-positive cases, along with 11 triple-negative breast carcinomas without apocrine differentiation, were evaluated for TRPS1 and GATA3 expression by immunohistochemistry. All tumors were diffusely positive (>90%) for androgen receptor (AR).

RESULTS.—

Triple-negative breast carcinoma with apocrine differentiation had positive TRPS1 expression in 12% of cases (5 of 41), whereas GATA3 was positive in all cases. Similarly, HER2+/ER- invasive breast carcinoma with apocrine differentiation showed positive TRPS1 in 18% of cases (2 of 11), whereas GATA3 was positive in all cases. In contrast, triple-negative breast carcinoma with strong AR expression but without apocrine differentiation showed both TRPS1 and GATA3 expression in 100% (11 of 11) of cases.

CONCLUSIONS.—

Most ER-/PR-/AR+ invasive breast carcinomas with apocrine differentiation are TRPS1 negative and GATA3 positive, regardless of HER2 status. Therefore, TRPS1 negativity does not exclude breast origin in tumors with apocrine differentiation. A panel of TRPS1 and GATA3 immunostains can be helpful when the tissue origin of such tumors is clinically relevant.

Androgen Receptor in Hormone Receptor-Positive Breast Cancer

Breast cancer subtypes expressing hormone receptors (HR+ BCa) have a good prognosis and respond to first-line endocrine therapy (ET). However, the majority of HR+ BCa patients exhibit intrinsic or acquired ET resistance (ET-R) and rapid onset of incurable metastatic BCa. With the failure of conventional ET, limited targeted therapy exists for ET-R HR+ BCa patients. The androgen receptor (AR) in HR-negative BCa subtypes is emerging as an attractive alternative target for therapy. The AR drives Luminal AR (LAR) triple-negative breast cancer progression, and LAR patients consistently exhibit positive clinical benefits with AR antagonists in clinical trials. In contrast, the function of the AR in HR+ BCa is more conflicting. AR in HR+ BCa correlates with a favorable prognosis, and yet, the AR supports the development of ET-R BCa. While AR antagonists were ineffective, ongoing clinical trials with a selective AR modulator have shown promise for HR+ BCa patients. To understand the incongruent actions of ARs in HR+ BCa, the current review discusses how the structure and post-translational modification impact AR function. Additionally, completed and ongoing clinical trials with FDA-approved AR-targeting agents for BCa are presented. Finally, we identify promising investigational small molecules and chimera drugs for future HR+ BCa therapy.

Is the Androgen Receptor a Viable Target in Triple Negative Breast Cancer in 5 Years?

Triple negative breast cancer (TNBC) is characterized by high rates of disease recurrence after definitive therapy, and median survival of less than 18 months in the metastatic setting. Systemic therapy options for TNBC consist primarily of cytotoxic chemotherapy-containing regimens, and while recently FDA-approved chemo-immunotherapy combinations and antibody-drug conjugates such as Sacituzumab govitecan have improved clinical outcomes, there remains an unmet need for more effective and less toxic therapies. A subset of TNBC expresses the androgen receptor (AR), a nuclear hormone steroid receptor that activates an androgen-responsive transcriptional program, and gene expression profiling has revealed a TNBC molecular subtype with AR expression and luminal and androgen responsive features. Both preclinical and clinical data suggest biologic similarities between luminal AR (LAR) TNBC and ER+ luminal breast cancer, including lower proliferative activity, relative chemoresistance, and high rates of oncogenic activating mutations in the phosphatidylinositol-3-kinase (PI3K) pathway. Preclinical LAR-TNBC models are sensitive to androgen signaling inhibitors (ASIs), and particularly given the availability of FDA-approved ASIs with robust efficacy in prostate cancer, there has been great interest in targeting this pathway in AR+ TNBC. Here, we review the underlying biology and completed and ongoing androgen-targeted therapy studies in early stage and metastatic AR+ TNBC.

Molecular features of androgen-receptor low, estrogen receptor-negative breast cancers in the Carolina breast cancer study

PURPOSE

Androgen receptor (AR) expression is absent in 40-90% of estrogen receptor (ER)-negative breast cancers. The prognostic value of AR in ER-negative patients and therapeutic targets for patients absent in AR remains poorly explored.

METHODS

We used an RNA-based multigene classifier to identify AR-low and AR-high ER-negative participants in the Carolina Breast Cancer Study (CBCS; N = 669) and The Cancer Genome Atlas (TCGA; N = 237). We compared AR-defined subgroups by demographics, tumor characteristics, and established molecular signatures [PAM50 risk of recurrence (ROR), homologous recombination deficiency (HRD), and immune response].

RESULTS

AR-low tumors were more prevalent among younger (RFD =  + 10%, 95% CI = 4% to 16%) participants in CBCS and were associated with HER2 negativity (RFD = - 35%, 95% CI = - 44% to - 26%), higher grade (RFD =  + 17%, 95% CI = 8% to 26%), and higher risk of recurrence scores (RFD =  + 22%, 95% CI = 16.1% to 28%), with similar results in TCGA. The AR-low subgroup was strongly associated with HRD in CBCS (RFD =  + 33.3%, 95% CI = 23.8% to 43.2%) and TCGA (RFD =  + 41.5%, 95% CI = 34.0% to 48.6%). In CBCS, AR-low tumors had high adaptive immune marker expression.

CONCLUSION

Multigene, RNA-based low AR expression is associated with aggressive disease characteristics as well as DNA repair defects and immune phenotypes, suggesting plausible precision therapies for AR-low, ER-negative patients.

Core Needle Biopsy Accuracy for Androgen Receptor Expression in Invasive Breast Cancer

OBJECTIVE

 Breast cancer (BC) biomarkers, such as hormone receptors expression, are crucial to guide therapy in BC patients. Antiandrogens have been studied in BC; however, limited data are available on androgen receptor (AR) expression test methodology. We aim to report the core needle biopsy (CNB) accuracy for AR expression in BC.

METHODS

 Patients diagnosed with stage I-III invasive BC from a single institution were included. Androgen receptor expression was evaluated by immunohistochemistry (IHC) using 1 and 10% cutoff and the AR expression in surgical specimens (SS) was the gold standard. Kappa coefficients were used to evaluate the intraprocedural agreement.

RESULTS

 A total of 72 patients were included, with a mean age of 61 years old and 84% were Luminal A or B tumors. The prevalence of AR expression in all BC samples was 87.5% using a cutoff ≥ 10% in SS. With a cutoff value ≥ 1%, CNB had an accuracy of 95.8% (Kappa value = 0.645; 95% confidence interval [CI]: 0.272-1.000; p < 0.001) and 86.1% (Kappa value = 0.365; 95% CI: 0.052-0.679; p < 0.001) when ≥ 10% cutoff was used for AR positivity. Androgen receptor expression in CNB (cutoff ≥ 1%) had a sensitivity of 98.5%, specificity of 60%, positive predictive value of 97.0%, and a negative predictive value of 76.9% in the detection of AR expression in SS.

CONCLUSION

 Core needle biopsy has good accuracy in evaluating AR expression in BC. The accuracy of CNB decreases with higher cutoff values for AR positivity.

Androgens Modulate Bcl-2 Agonist of Cell Death (BAD) Expression and Function in Breast Cancer Cells

Androgen receptor (AR) expression in estrogen receptor-positive (ER+) breast cancer (BC) correlates with lower tumor grade and a better clinical outcome. Additionally, in normal mammary epithelium or ER+ BC preclinical models, androgens counteract basal/ER-dependent proliferation. Here, we report an additional mechanism, underlining the protective role exerted by AR. Specifically, the activation of intracellular AR upregulates the Bcl-2-family protein BAD, and TCGA database analyses show that in ER+ BC, BAD expression is associated with better disease-free survival. Ligand-activated AR influences its own and BAD cellular compartmentalization by enhancing levels in the nucleus, as well as in mitochondrial fractions. In both compartments, BAD exerts unconventional functions. In the nucleus, BAD and AR physically interact and, upon androgen stimulation, are recruited at the AP-1 and ARE sites within the cyclin D1 promoter region, contributing to explaining the anti-proliferative effect of androgens in BC cells. Androgens cause an enrichment in BAD and AR content in the mitochondria, correlated with a decrease in mitochondrial function. Thus, we have defined a novel mechanism by which androgens modulate BAD expression, its mitochondria localization, and nuclear content to force its ability to act as a cell cycle inhibitor, strengthening the protective role of androgen signaling in estrogen-responsive BCs.

Advances in the Management of Early-Stage Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with both inter- and intratumor heterogeneity, thought to result in a more aggressive course and worse outcomes. Neoadjuvant therapy (NAT) has become the preferred treatment modality of early-stage TNBC as it allows for the downstaging of tumors in the breast and axilla, monitoring early treatment response, and most importantly, provides important prognostic information that is essential to determining post-surgical therapies to improve outcomes. It focuses on combinations of systemic drugs to optimize pathologic complete response (pCR). Excellent response to NAT has allowed surgical de-escalation in ideal candidates. Further, treatment algorithms guide the systemic management of patients based on their pCR status following surgery. The expanding knowledge of molecular pathways, genomic sequencing, and the immunological profile of TNBC has led to the use of immune checkpoint inhibitors and targeted agents, including PARP inhibitors, further revolutionizing the therapeutic landscape of this clinical entity. However, subgroups most likely to benefit from these novel approaches in TNBC remain elusive and are being extensively studied. In this review, we describe current practices and promising therapeutic options on the horizon for TNBC, surgical advances, and future trends in molecular determinants of response to therapy in early-stage TNBC.

Androgen Receptor Is Expressed in the Majority of Breast Cancer Brain Metastases and Is Subtype-Dependent

We aimed to evaluate the expression of the "targetable" androgen receptor (AR) in breast cancer brain metastases (BrM). An established, retrospective 57-patient cohort with metastatic breast cancer who underwent surgery for BrM at the Sunnybrook Odette Cancer Centre between 1999-2013 was studied. AR expression in BrM samples was assessed in triplicate using immunohistochemistry (IHC). AR positive status was defined as nuclear AR expression ≥ 10% by IHC using the SP107 antibody. The median age of patients was 52 years (range 32-85 years). 28 (49%) of BrM were HER2+, 17 (30%) were hormone receptor positive (HR+)/HER2-, and 12 (21%) were triple negative breast cancers (TNBCs). 56% (n = 32/57) of BrM were AR positive, and median AR expression was 20% (CI 1.6-38.3%). AR expression was different across breast cancer subtypes; AR was most frequently expressed in HER2+ (n = 21/28), followed by HR+/HER2- (n = 9/17), and lowest in TNBC (n = 2/12) BrM (p = 0.003). Patients with AR positive versus AR negative BrM had similar overall survival (12.5 vs. 7.9 months, p = 0.6), brain-specific progression-free survival (8.0 vs. 5.1 months, p = 0.95), and time from breast cancer diagnosis to BrM diagnosis (51 vs. 29 months, p = 0.16). AR is expressed in the majority of breast cancer BrM and represents a potential 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.

TROP2, androgen receptor, and PD-L1 status in histological subtypes of high-grade metaplastic breast carcinomas

AIMS

High-grade metaplastic breast carcinoma (HG-MBC) is a rare subtype of invasive breast carcinoma, mostly triple-negative. Metaplastic carcinomas are less responsive to neoadjuvant chemotherapy and are associated with a worse outcome than invasive carcinomas of no special type.

METHODS

Clinicopathological characteristics and immunophenotype were retrospectively assessed in a series of 65 patients diagnosed with HG-MBC between 2005 and 2017 at the Curie Institute (antibody panel: oestrogen receptor [ER], progesterone receptor [PR], androgen receptor [AR], human epidermal growth factor receptor 2 [HER2], programmed death ligand-1 [PD-L1], and trophoblast cell surface antigen 2 [TROP2]).

RESULTS

The median age at diagnosis was 59.5 years. Six (9%) patients had metastatic disease at diagnosis. Among the nonmetastatic patients receiving neoadjuvant therapy, 26% (5/19) achieved pathological complete response. Most tumours were pT1/pT2 (77%) and 12% were pN+. Histological subtypes (mixed, squamous, mesenchymal, and spindle cell) were 40%, 35.5%, 15.5%, and 9%, respectively. Tumour-infiltrating lymphocytes were low or moderate except when squamous differentiation was present. Most tumours were triple-negative (92%). AR and TROP2 were positive in 34% and 85% of the cases, respectively. PD-L1 was positive in tumour cells in 18% (cutoff: 1% of positive tumour cells) of the cases and in tumour-infiltrating immune cells in 40% (cutoff: 1% of tumour area) of the cases. Notably, spindle cell and mesenchymal metaplastic breast carcinomas were mostly PDL1-negative. Lastly, 21 (32.3%) cases were HER2-low, all being HER2 1+, with no HER2 2+.

CONCLUSION

Metaplastic breast carcinoma could benefit from tailored therapeutic strategies adapted to the phenotypic specificities of histological subtypes.

Molecular Features of Androgen-Receptor Low, Estrogen Receptor-Negative Breast Cancers in the Carolina Breast Cancer Study

PURPOSE

Androgen receptor (AR) expression is absent in 40-90% of estrogen receptor (ER)-negative breast cancers. The prognostic value of AR in ER-negative patients and therapeutic targets for patients absent in AR remains poorly explored.

METHODS

We used an RNA-based multigene classifier to identify AR-low and AR-high ER-negative participants in the Carolina Breast Cancer Study (CBCS; n=669) and The Cancer Genome Atlas (TCGA; n=237). We compared AR-defined subgroups by demographics, tumor characteristics, and established molecular signatures [PAM50 risk of recurrence (ROR), homologous recombination deficiency (HRD), and immune response].

RESULTS

AR-low tumors were more prevalent among Black (relative frequency difference (RFD) = +7%, 95% CI = 1% to 14%) and younger (RFD = +10%, 95% CI = 4% to 16%) participants in CBCS and were associated with HER2-negativity (RFD = -35%, 95% CI = -44% to -26%), higher grade (RFD = +17%, 95% CI = 8% to 26%), and higher risk of recurrence scores (RFD = +22%, 95% CI = 16.1% to 28%), with similar results in TCGA. The AR-low subgroup was strongly associated with HRD in CBCS (RFD = +33.3%, 95% CI = 23.8% to 43.2%) and TCGA (RFD = +41.5%, 95% CI = 34.0% to 48.6%). In CBCS, AR-low tumors had high adaptive immune marker expression.

CONCLUSION

Multigene, RNA-based low AR expression is associated with aggressive disease characteristics as well as DNA repair defects and immune phenotypes, suggesting plausible precision therapies for AR-low, ER-negative patients.

Marker assessments in ER-positive breast cancers: old markers, new applications?

Evaluation of oestrogen receptor (ER) expression by immunostaining is essential in the pathological assessment of breast cancer. Its expression is intercorrelated with clinicopathological features, molecular typing, and treatment selection. The development of novel therapeutic agents related to ER status, the recent ASCO introduction of an ER-low positive category of breast cancers, and the ever-increasing plethora of diagnostic and theragnostic markers call for a timely update. In this article we aim to review the clinicopathological features of ER-positive breast cancers, with an emphasis on ER-low positive breast cancers, and a focus on updating the (i) assessment, reporting and interpretation of ER immunohistochemical (IHC) staining, (ii) correlations of ER status with other diagnostic and theragnostic markers, and (iii) implications for treatment selection and response. In the face of the developments in IHC and molecular techniques and targeted therapy, ER immunostaining is still expected to remain as the core component of prognostic and theragnostic assessment of breast cancers.

Modulating the Activity of Androgen Receptor for Treating Breast Cancer

The androgen receptor (AR) is a steroid hormone receptor widely detected in breast cancer. Evidence suggests that the AR might be a tumor suppressor in estrogen receptor alpha-positive (ERα+ve) breast cancer but a tumor promoter in estrogen receptor alpha-negative (ERα-ve) breast cancer. Modulating AR activity could be a potential strategy for treating breast cancer. For ERα+ve breast cancer, activation of the AR had been demonstrated to suppress the disease. In contrast, for ERα-ve breast cancer, blocking the AR could confer better prognosis to patients. These studies support the feasibility of utilizing AR modulators as anti-cancer drugs for different subtypes of breast cancer patients. Nevertheless, several issues still need to be addressed, such as the lack of standardization in the determination of AR positivity and the presence of AR splice variants. In future, the inclusion of the AR status in the breast cancer report at the time of diagnosis might help improve disease classification and treatment decision, thereby providing additional treatment strategies for 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.

Proxalutamide in patients with AR-positive metastatic breast cancer: Results from an open-label multicentre phase Ib study and biomarker analysis

AIM

Proxalutamide is a novel second-generation non-steroidal androgen receptor (AR) antagonist. This study aimed to evaluate the preliminary efficacy and safety of proxalutamide in patients with AR-positive metastatic breast cancer (AR⁺ mBC).

METHODS

In this open-label, dose-expansion, multicentre phase Ib trial, patients with AR⁺ mBC (immunohistochemistry [IHC] ≥1%) received proxalutamide orally once daily. Two proxalutamide dose cohorts (cohort A: 200 mg; cohort B: 300 mg) were sequentially investigated. Primary endpoints were disease control rate (DCR) at 8 and 16 weeks and recommended phase II dose (RP2D).

RESULTS

Forty-five patients with three median lines (range, 1-13) prior systemic therapy were enrolled (cohort A, n = 30; cohort B, n = 15). Among 39 evaluable patients, DCR at 8 and 16 weeks was 25.6% (95% confidence interval [CI], 11.9-39.4%), with 26.9% in cohort A and 23.1% in cohort B. No patient achieved partial response or complete response. Proxalutamide 200 mg/day was determined as RP2D. The 6-month progression-free survival (PFS) rate was 19.6% (95% CI, 10.2-37.5%). In the triple-negative subgroup, DCR at 8 weeks was 38.5%, with median PFS of 9.1 months (95% CI, 7.8-NA) in those who achieved response at 8 weeks (n = 5). Most common grade 3/4 adverse events were aspartate aminotransferase increase (8.9%) and γ-glutamyltransferase increase (8.9%). By biomarker analysis, patients with moderate AR expression of IHC (26%-75%), PIK3CA pathogenic mutations, or <60 ng/ml cell-free DNA yield showed longer PFS.

CONCLUSION

Proxalutamide showed promising anti-tumour activity with good tolerability in patients with heavily pretreated AR⁺ mBC, supporting further investigation.

TRIAL REGISTRATION

This clinical study was prospectively registered at chinadrugtrials.org.cn (Identifier: CTR20170757) and clinical trials.gov (Identifier: NCT04103853).

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.

Association of androgen receptor expression with glucose metabolic features in triple-negative breast cancer

Background

Androgen receptor (AR) is a potential therapeutic target in triple-negative breast cancer (TNBC). We aimed to elucidate the association of AR expression with glucose metabolic features in TNBC.

Methods

Two independent datasets were analyzed: FDG PET data of our institution and a public dataset of GSE135565. In PET analysis, patients with TNBC who underwent pretreatment PET between Jan 2013 and Dec 2017 were retrospectively enrolled. Clinicopathologic features and maximum standardized uptake value (SUVmax) of tumors were compared with AR expression. In GSE135565 dataset, glycolysis score was calculated by the pattern of glycolysis-related genes, and of which association with SUVmax and AR gene expression were analyzed.

Results

A total of 608 female patients were included in the PET data of our institution. SUVmax was lower in AR-positive tumors (P < 0.001) and correlated with lower AR expression (rho = –0.26, P < 0.001). In multivariate analysis, AR was a deterministic factor for low SUVmax (P = 0.012), along with other key clinicopathologic features. In the GSE135565 dataset, AR expression also exhibited a negative correlation with SUVmax (r = –0.34, P = 0.001) and the glycolysis score (r = –0.27, P = 0.013).

Conclusions

Low glucose metabolism is a signature of AR expression in TNBC. It is suggested that evaluation of AR expression status needs to be considered in clinical practice particularly in TNBC with low glucose metabolism.

Racial Disparity in Quadruple Negative Breast Cancer: Aggressive Biology and Potential Therapeutic Targeting and Prevention

Simple Summary

Quadruple negative breast cancer (QNBC), a subgroup of triple negative BC, has emerged as a highly aggressive BC subtype that disproportionately afflicts and impacts Black/African-American (AA) women. In this article, we review molecular distinctions in Black/AA and White/European-American (EA) QNBC biology as well as address potential non-genetic risk factors that could be underlying this racially disparate burden. We aim to provide deeper insight and provide a framework for novel discovery of actionable therapeutic targets and identify lifestyle changes to improve outcomes for Black/AA QNBC patients.

Abstract

Black/African-American (AA) women, relative to their White/European-American (EA) counterparts, experience disproportionately high breast cancer mortality. Central to this survival disparity, Black/AA women have an unequal burden of aggressive breast cancer subtypes, such as triple-negative breast cancer (ER/PR-, HER2-wild type; TNBC). While TNBC has been well characterized, recent studies have identified a highly aggressive androgen receptor (AR)-negative subtype of TNBC, quadruple-negative breast cancer (ER/PR-, HER2-wildtype, AR-; QNBC). Similar to TNBC, QNBC disproportionately impacts Black/AA women and likely plays an important role in the breast cancer survival disparities experienced by Black/AA women. Here, we discuss the racial disparities of QNBC and molecular signaling pathways that may contribute to the aggressive biology of QNBC in Black/AA women. Our immediate goal is to spotlight potential prevention and therapeutic targets for Black/AA QNBC; ultimately our goal is to provide greater insight into reducing the breast cancer survival burden experienced by Black/AA women.

Deciphering clinical significance of BCL11A isoforms and protein expression roles in triple-negative breast cancer subtype

Purpose

Triple negative breast cancer (TNBC) is an aggressive clinical tumor, accounting for about 25% of breast cancer (BC) related deaths. Chemotherapy is the only therapeutic option to treat TNBC, hence a detailed understanding of the biology and its categorization is required. To investigate the clinical relevance of BCL11A in TNBC subtype, we focused on gene and protein expression and its mutational status in a large cohort of this molecular subtype.

Methods

Gene expression profiling of BCL11A and its isoforms (BCL11A-XL, BCL11A-L and BCL11A-S) has been determined in Luminal A, Luminal B, HER2-enriched and TNBC subtypes. BCL11A protein expression has been analyzed by immunohistochemistry (IHC) and its mutational status by Sanger sequencing.

Results

In our study, BCL11A was significantly overexpressed in TNBC both at transcriptional and translational levels compared to other BC molecular subtypes. A total of 404 TNBCs were selected and examined showing a high prevalence of BCL11A-XL (37.3%) and BCL11A-L (31.4%) isoform expression in TNBC, associated with a 26% of BCL11A protein expression levels. BCL11A protein expression predicts scarce LIV (HR = 0.52; 95% CI, 0.29–0.92, P = 0.03) and AR downregulation (HR = 0.37; 95% CI, 0.16–0.88; P = 0.02), as well as a higher proliferative index in TNBC cells. BCL11A-L expression is associated with more aggressive TNBC histological types, such as medullary and metaplastic carcinoma.

Conclusion

Our finding showed that BCL11A protein expression acts as an unfavorable prognostic factor in TNBC patients, especially in non luminal TNBCs subgroups. These results may yield a better treatment strategy by providing a new parameter for TNBC classification.

Correlation of TBK1, AR, and other serum cancer-related biomarkers in breast cancer patients: An observational study

Breast cancer (BC) ranks first for incidence and mortality in gynecological malignant tumors. This study aims to investigate the diagnostic value of Tank-binding kinase 1 (TBK1) and its correlation with androgen receptor (AR) and other serum cancer-related biomarkers in BC patient. The present observational study included 451 female BC patients and 451 healthy controls. Serum levels of TBK1, AR and other cancer-related biomarkers were detected in all the patients and healthy controls. Patients' demographic data and clinical data including age, body mass index (BMI), tumor node Metastasis (TNM), pathological type, tumor size and lymph node metastasis were collected. The follow-up lasted for 5 years. The deceased group had higher rate of patients with TNM III~IV, lymph node metastasis or tumor diameter >2. Deceased group had much higher rate of patients with negative ER and positive Ki67. Besides, increased TBK1 was found in BC patients with positive correlation with AR, CA15-3, CA125, CEA, and CA19-9. Serum TBK1 was associated with the clinic outcomes of BC patients and those with high TBK1 had lower 5-year survival rate. Moreover, cutoff value of 13.95 ng/mL TBK1 showed AUC of 0.981 (93.6% for sensitivity and 86.3% for specificity) for diagnosing BC, and cutoff value of 22.65 ng/mL TBK1 had AUC of 0.996 (97.7% for sensitivity and 96.3% for specificity) for diagnosing the death of BC patients. Serum TBK1 was positively correlated with AR and other serum cancer-related biomarkers. In addition, high TBK1 predicted the poor prognosis and might be used for the diagnosis of BC.

HC-1119, a deuterated Enzalutamide, inhibits Migration, Invasion and Metastasis of the AR-positive triple-negative breast Cancer cells

Triple-negative breast cancers (TNBCs) are aggressive, and they develop metastasis at earlier stages, relapse more frequently, and exhibits poorer prognosis than other subtypes of breast cancer. Due to the lack of estrogen receptor for endocrine therapy and HER2 for targeted therapy, new targeted therapies for TNBCs are urgently needed. Enzalutamide is a second-generation androgen receptor (AR) inhibitor, and HC-1119 is a new synthetic deuterated enzalutamide. Owing to the isotope effect, HC-1119 has many advantages over enzalutamide, including slow metabolism, high plasma concentration and low brain exposure. However, the efficacy of HC-1119 in inhibition of AR function in triple-negative breast cancer (TNBC) has not been studied. In this study, we found high-level AR expression in both Hs578T and SUM159PT TNBC cell lines. Activation of AR by dihydrotestosterone (DHT) in both cell lines increased AR protein, induced AR-nuclear localization, enhanced cell migration and invasion in culture, and promoted liver metastasis in mice. Importantly, cotreatment with HC-1119 of these cells efficiently abolished all of these effects of DHT on both Hs578T and SUM159PT cells. These results indicate that HC-1119 is a very effective new second-generation AR antagonist that can inhibit the migration, invasion and metastasis of the AR-positive TNBC cells.

Precision Breast Cancer Medicine: Early Stage Triple Negative Breast Cancer-A Review of Molecular Characterisation, Therapeutic Targets and Future Trends

Personalised approaches to the management of all solid tumours are increasing rapidly, along with wider accessibility for clinicians. Advances in tumour characterisation and targeted therapies have placed triple-negative breast cancers (TNBC) at the forefront of this approach. TNBC is a highly heterogeneous disease with various histopathological features and is driven by distinct molecular alterations. The ability to tailor individualised and effective treatments for each patient is of particular importance in this group due to the high risk of distant recurrence and death. The mainstay of treatment across all subtypes of TNBC has historically been cytotoxic chemotherapy, which is often associated with off-target tissue toxicity and drug resistance. Neoadjuvant chemotherapy is commonly used as it allows close monitoring of early treatment response and provides valuable prognostic information. Patients who achieve a complete pathological response after neoadjuvant chemotherapy are known to have significantly improved long-term outcomes. Conversely, poor responders face a higher risk of relapse and death. The identification of those subgroups that are more likely to benefit from breakthroughs in the personalised approach is a challenge of the current era where several targeted therapies are available. This review presents an overview of contemporary practice, and promising future trends in the management of early TNBC. Platinum chemotherapy, DNA damage response (DDR) inhibitors, immune checkpoint inhibitors, inhibitors of the PI3K-AKT-mTOR, and androgen receptor (AR) pathways are some of the increasingly studied therapies which will be reviewed. We will also discuss the growing evidence for less-developed agents and predictive biomarkers that are likely to contribute to the forthcoming advances in this field. Finally, we will propose a framework for the personalised management of TNBC based upon the integration of clinico-pathological and molecular features to ensure that long-term outcomes are optimised.

Antiandrogen Therapy Radiosensitizes Androgen Receptor-Positive Cancers to 18F-FDG

A subset (35%) of triple-negative breast cancers (TNBCs) expresses androgen receptor (AR) activity. However, clinical trials with antiandrogen drugs have shown limited efficacy, with about a 19% clinical benefit rate. We investigated the therapeutic enhancement of antiandrogens as radiosensitizers in combination with ¹⁸F-FDG in TNBC. Methods: We screened 5 candidate drugs to evaluate shared toxicity when combined with either ¹⁸F-FDG, x-rays, or ultraviolet radiation, at doses below their respective half-maximal inhibitory concentrations. Cytotoxic enhancement of antiandrogen in combination with ¹⁸F-FDG was evaluated using cell proliferation and DNA damage assays. Finally, the therapeutic efficacy of the combination treatment was evaluated in mouse tumor models of TNBC and prostate cancer. Results: Bicalutamide, an antiandrogen drug, was found to share similar toxicity in combination with either ¹⁸F-FDG or x-rays, indicating its sensitivity as a radiosensitizer to ¹⁸F-FDG. Cell proliferation assays demonstrated selective toxicity of combination bicalutamide-¹⁸F-FDG in AR-positive 22RV1 and MDA-MB-231 cells in comparison to AR-negative PC3 cells. Quantitative DNA damage and cell cycle arrest assays further confirmed radiation-induced damage to cells, suggesting the role of bicalutamide as a radiosensitizer to ¹⁸F-FDG-mediated radiation damage. Animal studies in MDA-MB-231, 22RV1, and PC3 mouse tumor models demonstrated significant attenuation of tumor growth through combination of bicalutamide and ¹⁸F-FDG in the AR-positive model in comparison to the AR-negative model. Histopathologic examination corroborated the in vitro and in vivo data and confirmed the absence of off-target toxicity to vital organs. Conclusion: These data provide evidence that ¹⁸F-FDG in conjunction with antiandrogens serving as radiosensitizers has utility as a radiotherapeutic agent in the ablation of AR-positive cancers.

Rewiring of the Endocrine Network in Triple-Negative Breast Cancer

The immunohistochemical definition of estrogen/progesterone receptors dictates endocrine feasibility in the treatment course of breast cancer. Characterized by the deficiency of estrogen receptor α, ERα-negative breast cancers are dissociated from any endocrine regimens in the routine clinical setting, triple-negative breast cancer in particular. However, the stereotype was challenged by triple-negative breast cancers’ retained sensitivity and vulnerability to endocrine agents. The interplay of hormone action and the carcinogenic signaling program previously underscored was gradually recognized along with the increasing investigation. In parallel, the overlooked endocrine-responsiveness in ERα-negative breast cancers attracted attention and supplied fresh insight into the therapeutic strategy in an ERα-independent manner. This review elaborates on the genomic and non-genomic steroid hormone actions and endocrine-related signals in triple-negative breast cancers attached to the hormone insensitivity label. We also shed light on the non-canonical mechanism detected in common hormone agents to showcase their pleiotropic effects.

Therapeutic progress and challenges for triple negative breast cancer: targeted therapy and immunotherapy

Triple negative breast cancer (TNBC) is a subtype of breast cancer, with estrogen receptor, human epidermal growth factor receptor 2 and progesterone receptor negative. TNBC is characterized by high heterogeneity, high rates of metastasis, poor prognosis, and lack of therapeutic targets. Now the treatment of TNBC is still based on surgery and chemotherapy, which is effective only in initial stage but almost useless in advanced stage. And due to the lack of hormone target, hormonal therapies have little beneficial effects. In recent years, signaling pathways and receptor-specific targets have been reported to be effective in TNBC patients under specific clinical conditions. Now targeted therapies have been approved for many other cancers and even other subtypes of breast cancer, but treatment options for TNBC are still limited. Most of TNBC patients showed no response, which may be related to the heterogeneity of TNBC, therefore more effective treatments and predictive biomarkers are needed. In the present review, we summarize potential treatment opinions for TNBC based on the dysregulated receptors and signaling pathways, which play a significant role in multiple stages of TNBC development. We also focus on the application of immunotherapy in TNBC, and summarize the preclinical and clinical trials of therapy for patients with TNBC. We hope to accelerate the research and development of new drugs for TNBC by understanding the relevant mechanisms, and to improve survival.

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.

The Role of Androgen Receptor and microRNA Interactions in Androgen-Dependent Diseases

The androgen receptor (AR) is a member of the steroid hormone receptor family of nuclear transcription factors. It is present in the primary/secondary sexual organs, kidneys, skeletal muscles, adrenal glands, skin, nervous system, and breast. Abnormal AR functioning has been identified in numerous diseases, specifically in prostate cancer (PCa). Interestingly, recent studies have indicated a relationship between the AR and microRNA (miRNA) crosstalk and cancer progression. MiRNAs are small, endogenous, non-coding molecules that are involved in crucial cellular processes, such as proliferation, apoptosis, or differentiation. On the one hand, AR may be responsible for the downregulation or upregulation of specific miRNA, while on the other hand, AR is often a target of miRNAs due to their regulatory function on AR gene expression. A deeper understanding of the AR–miRNA interactions may contribute to the development of better diagnostic tools as well as to providing new therapeutic approaches. While most studies usually focus on the role of miRNAs and AR in PCa, in this review, we go beyond PCa and provide insight into the most recent discoveries about the interplay between AR and miRNAs, as well as about other AR-associated and AR-independent diseases.

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.

Prognostic Role of Androgen Receptor Expression in HER2+ Breast Carcinoma Subtypes

HER2+ breast cancer (BC) is an aggressive subtype representing a genetically and biologically heterogeneous group of tumors resulting in variable prognosis and treatment response to HER2-targeted therapies according to estrogen (ER) and progesterone receptor (PR) expression. The relationship with androgen receptors (AR), a member of the steroid hormone's family, is unwell known in BC. The present study aims to evaluate the prognostic impact of AR expression in HER2+ BC subtypes. A total of 695 BCs were selected and reviewed, AR, ER, PR and HER2 expression in tumor cells were examined by immunohistochemical method, and the SISH method was used in case of HER2 with equivocal immunohistochemical score (2+). A high prevalence of AR expression (91.5%) in BC HER+ was observed, with minimal differences between luminal and non-luminal tumor. According to steroid receptor expression, tumors were classified in four subgroups, including BC luminal and non-luminal HER2+ expressing or not AR. The luminal BC HER2 + AR+ was associated with lower histological grade, lower tumor size, higher PR expression and lower HER2 intensity of expression (2+). Also, the non-luminal tumors AR+ showed lower tumor size and lower prognostic stage but frequently higher grade and higher HER2 intensity of expression (3+). These findings should suggest a different progression of luminal and non-luminal tumors, both expressing AR, and allow us to speculate that the molecular mechanisms of AR, involved in the biology of BC HER2 + AR+, differ in relation to ER and PR expression. Moreover, AR expression may be a useful predictor of prognosis for overall survival (OS) in HER2+ BC subtypes. Our findings suggest that AR expression evaluation in clinical practice could be utilized in clinical oncology to establish different aggressiveness in BC HER2+ subtypes.

A triple-negative breast cancer surrogate subtype classification that correlates with gene expression subtypes

BACKGROUND

This study developed a triple-negative breast cancer (TNBC) surrogate subtype classification that represents TNBC subtypes based on the Vanderbilt subtype classification.

METHODS

Patients who underwent primary curative surgery for TNBC were included. Representative FFPE blocks were used for gene expression analysis and tissue microarray construction for immunohistochemical (IHC) staining. The Vanderbilt subtypes were re-classified into four groups: basal-like (BL), mesenchymal-like (M), immunomodulatory (IM) and luminal androgen receptor (LAR) subtype. Classification and regression tree (CART) modeling was applied to develop a surrogate subtype classification.

RESULTS

A total of 145 patients were included. The study cohort was allocated to the Vanderbilt 4 subtypes as LAR (n = 22, 15.2%), IM (n = 32, 22.1%), M (n = 38, 26.2%), BL (n = 25, 17.2%) and unclassified (n = 28, 19.3%). After excluding nine (6.2%) patients due to poor IHC staining quality, CART modeling was performed. TNBC surrogate subtypes were defined as follows: LAR subtype, androgen receptor Allred score 8; IM subtype, LAR-negative with a tumor-infiltrating lymphocyte (TIL) score > 70%; M subtype, LAR-negative with a TIL score < 20%; BL subtype, LAR-negative with a TIL score 20-70% and diffuse, strong p16 staining. The study cohort was classified by the surrogate subtypes as LAR (n = 26, 17.9%), IM (n = 21, 14.5%), M (n = 44, 30.3%), BL1 (n = 27, 18.6%) and unclassified (n = 18, 12.4%). Surrogate subtypes predicted TNBC Vanderbilt 4 subtypes with an accuracy of 0.708.

CONCLUSION

We have developed a TNBC surrogate subtype classification that correlates with the Vanderbilt subtype. It is a practical and accessible diagnostic test that can be easily applied in clinical practice.

Androgen Receptor as an Emerging Feasible Biomarker for Breast Cancer

Biomarkers can be used for diagnosis, prognosis, and prediction in targeted therapy. The estrogen receptor α (ERα) and human epidermal growth factor receptor 2 (HER2) are standard biomarkers used in breast cancer for guiding disease treatment. The androgen receptor (AR), a nuclear hormone receptor, contributes to the development and progression of prostate tumors and other cancers. With increasing evidence to support that AR plays an essential role in breast cancer, AR has been considered a useful biomarker in breast cancer, depending on the context of breast cancer sub-types. The existing survival analyses suggest that AR acts as a tumor suppressor in ER + ve breast cancers, serving as a favorable prognostic marker. However, AR functions as a tumor promoter in ER-ve breast cancers, including HER2 + ve and triple-negative (TNBC) breast cancers, serving as a poor prognostic factor. AR has also been shown to be predictive of the potential of response to adjuvant hormonal therapy in ER + ve breast cancers and to neoadjuvant chemotherapy in TNBC. However, conflicting results do exist due to intrinsic molecular differences between tumors and the scoring method for AR positivity. Applying AR expression status to guide treatment in different breast cancer sub-types has been suggested. In the future, AR will be a feasible biomarker for breast cancer. Clinical trials using AR antagonists in breast cancer are active. Targeting AR alone or other therapeutic agents provides alternatives to existing therapy for breast cancer. Therefore, AR expression will be necessary if AR-targeted treatment is to be used.

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.

Androgen receptor in breast cancer: The "5W" questions

Androgen receptor (AR) is expressed in 60-70% of breast cancers (BCs) and the availability of anti-AR compounds, currently used for treating prostate cancer, paves the way to tackle specifically AR-positive BC patients. The prognostic and predictive role of AR in BC is a matter of debate, since the results from clinical trials are not striking, probably due to both technical and biological reasons. In this review, we aimed to highlight WHAT is AR, describing its structure and functions, WHAT to test and HOW to detect AR, WHERE AR should be tested (on primary tumor or metastasis) and WHY studying this fascinating hormone receptor, exploring and debating on its prognostic and predictive role. We considered AR and its ratio with other hormone receptors, analyzing also studies including patients with ductal carcinoma in situ and with early and advanced BC, as well. We also emphasized the effects that both other hormone receptors and the newly emerging androgen-inducible non coding RNAs may have on AR function in BC pathology and the putative implementation in the clinical setting. Moreover, we pointed out the latest results by clinical trials and we speculated about the use of anti-AR therapies in BC clinical practice.

The Other Side of the Coin: May Androgens Have a Role in Breast Cancer Risk?

Breast cancer prevention is a major challenge worldwide. During the last few years, efforts have been made to identify molecular breast tissue factors that could be linked to an increased risk of developing the disease in healthy women. In this concern, steroid hormones and their receptors are key players since they are deeply involved in the growth, development and lifetime changes of the mammary gland and play a crucial role in breast cancer development and progression. In particular, androgens, by binding their own receptor, seem to exert a dichotomous effect, as they reduce cell proliferation in estrogen receptor α positive (ERα+) breast cancers while promoting tumour growth in the ERα negative ones. Despite this intricate role in cancer, very little is known about the impact of androgen receptor (AR)-mediated signalling on normal breast tissue and its correlation to breast cancer risk factors. Through an accurate collection of experimental and epidemiological studies, this review aims to elucidate whether androgens might influence the susceptibility for breast cancer. Moreover, the possibility to exploit the AR as a useful marker to predict the disease will be also evaluated.

An Update on the Molecular and Clinical Characteristics of Apocrine Carcinoma of the Breast

Apocrine carcinoma of the breast is a rare malignancy. According to 2019 WHO classification, apocrine cellular features and a characteristic steroid receptor profile (Estrogen receptor (ER)-negative and androgen receptor (AR)-positive) define apocrine carcinoma. Her-2/neu protein expression is reported in ∼30-50% of apocrine carcinomas, while NGS analysis showed frequent PIK3CA/PTEN/AKT and TP53 mutations Followed by deregulation in the mitogen-activated protein kinase pathway components (mutations of KRAS, NRAS, BRAF). A recent miRNA study indicates various miRNAs (downregulated hsa-miR-145-5p and upregulated 14 miRNAs such as hsa-miR-182-5p, hsa-miR-3135b, and hsa-miR-4417) may target the commonly altered pathways in apocrine carcinomas such as ERBB2/HER2 and mitogen-activated protein kinase signaling pathway. Although AR expression is a hallmark of apocrine carcinoma, little is known regarding the efficacy/resistance to antiandrogens. Success of bicalutamide, a non-steroidal anti-androgen, was reported in a case of Her2-negative apocrine carcinoma. Two recent studies, however, described presence of anti-androgen resistance biomarkers (a splice variant ARv7 and AR/NCOA2 co-amplification) in a subset of AR+ apocrine carcinomas, cautioning the use of anti-androgens in AR+ triple-negative breast carcinomas. Apocrine carcinomas rarely show biomarkers predictive of response to immune checkpoint inhibitors (PD-L1 expression, MSI-H status, and TMB-high). Therefore, a comprehensive cancer profiling of apocrine carcinomas is necessary to identify potential therapeutic targets for a truly individualized treatment approach.

Is it time to consider the Androgen receptor as a therapeutic target in breast cancer?

Breast cancer (BC) is a heterogeneous disease and the most prevalent malignant tumor in women worldwide. The majority of BC cases are positive for estrogen receptor (ER) and progesterone receptor (PgR), both known to be involved in cancer pathogenesis, progression, and invasion. In line with this, hormonal deprivation therapy appears to be a useful tool and an effective treatment for these BC subtypes. Unfortunately, prognosis among patients with hormone-negative tumors or therapy-refractory and metastatic patients remains poor. Novel biomarkers are urgently needed in order to predict the course of the disease, make better therapy decisions and improve the overall survival of patients. In this respect, the androgen receptor (AR), a member of the hormonal nuclear receptor superfamily and ER and PgR, emerges as an interesting feature widely expressed in human BCs. Despite the advances, the precise tumorigenic mechanism of AR and the role of its endogenous ligands are yet not well-understood. In this review, we aim to elaborate on the prognostic impact of AR expression and current AR-targeting approaches based on previous studies investigating AR's role in different BC subtypes.

Androgen Receptor is Expressed in Breast Cancer Brain Metastases

BACKGROUND

Androgen receptor (AR) expression is a potential therapeutic target in breast cancer (BC) as it is frequently expressed in the luminal A and B subtypes and in approximately one third of basal-like cancers. As AR-positive BC displays a distinct biological behavior, we aimed to analyze AR expression in the particular context of BC brain metastases (BM).

MATERIALS AND METHODS

Patients with newly diagnosed BC BM treated with neurosurgical resection were identified from the Vienna Brain Metastasis Registry and clinical data including patient characteristics, biological tumor subtypes and overall survival were obtained by retrospective chart review. Formalin-fixed and paraffin-embedded specimen containing BM tissue were retrieved from the Neuro-Biobank. Immunohistochemical staining of AR was performed and AR expression in the tumor-cell nucleus was evaluated.

RESULTS

Fifty-seven BM samples from 57 individual patients with BC were available for this analysis. AR expression of ≥1% tumor cells was evident in 20/57 (35.1%) BM specimens; the median AR-expression rate was 10% (range: 1% to 60%). AR expression was observed in 11/21 (52.4%) BM of the luminal/human epidermal growth factor receptor 2 (HER2)-negative subtype, 3/13 (23.1%) of the luminal/HER2-positive subtype, 2/7 (28.6%) of the HER2-positive subtype and 4/16 (25.0%) of the triple-negative subtype (P=0.247). Median survival from diagnosis of BM was 10 months (range: 0 to 104 mo) in the entire cohort. No significant association of overall survival and AR expression ≥1% was observed (15 vs. 13 mo; P>0.05).

CONCLUSION

AR is expressed in more than one third of BC BM with the highest rates among the luminal/HER2-negative BC subtype and may therefore be a potential prognostic and predictive biomarker in this particular BC population.

QNBC Is Associated with High Genomic Instability Characterized by Copy Number Alterations and miRNA Deregulation

Triple-negative breast cancer (TNBC) can be further classified into androgen receptor (AR)-positive TNBC and AR-negative TNBC or quadruple-negative breast cancer (QNBC). Here, we investigated genomic instability in 53 clinical cases by array-CGH and miRNA expression profiling. Immunohistochemical analysis revealed that 64% of TNBC samples lacked AR expression. This group of tumors exhibited a higher level of copy number alterations (CNAs) and a higher frequency of cases affected by CNAs than TNBCs. CNAs in genes of the chromosome instability 25 (CIN25) and centrosome amplification (CA) signatures were more frequent in the QNBCs and were similar between the groups, respectively. However, expression levels of CIN25 and CA20 genes were higher in QNBCs. miRNA profiling revealed 184 differentially expressed miRNAs between the groups. Fifteen of these miRNAs were mapped at cytobands with CNAs, of which eight (miR-1204, miR-1265, miR-1267, miR-23c, miR-548ai, miR-567, miR-613, and miR-943), and presented concordance of expression and copy number levels. Pathway enrichment analysis of these miRNAs/mRNAs pairings showed association with genomic instability, cell cycle, and DNA damage response. Furthermore, the combined expression of these eight miRNAs robustly discriminated TNBCs from QNBCs (AUC = 0.946). Altogether, our results suggest a significant loss of AR in TNBC and a profound impact in genomic instability characterized by CNAs and deregulation of miRNA expression.

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.

Molecular Classification of Triple Negative Breast Cancer and the Emergence of Targeted Therapies

Triple negative breast cancer (TNBC) represents 15% to 20% of all primary breast cancers and is the most aggressive subtype of breast cancer. There has been rapid progress in targeted therapy and biomarker development to identify the optimal treatments for TNBC. To update recent developments, this article comprehensively reviews molecular classification and biomarkers of TNBC and targeted therapy developments in immunotherapy, PARP and AKT pathway inhibitors, antibody-drug conjugates and androgen receptor blockade. The treatment of TNBC has dramatically evolved beyond basic cytotoxic chemotherapy into an expanding domain of targeted therapies tailored to the heterogeneity of this complex and aggressive disease. Progress will continue through the sustained and devoted efforts of our investigators and the patients who dedicatedly enroll in clinical trials. Through a daring persistence to challenge the status quo we now have the opportunity to offer our patients with TNBC a new sense of hope.

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.