The androgen receptor as a surrogate marker for molecular apocrine breast cancer subtyping

Androgen Receptor Expression in ER and PR Negative Breast Cancer-A Study from a Tertiary Hospital in Northern India

Sumeet SidhuObjectives  Breast cancer is the leading cause of cancer-related deaths in women. Estrogen (ER) and progesterone receptor (PR) status and Her2 overexpression are major determinants in therapeutic decision making. Triple-negative breast cancers (TNBCs) have limited treatment options. Androgen receptor (AR) expression opens up therapeutic avenues for these patients. The aim of this article was to study the immunohistochemical expression of ARs in ER and PR Negative breast carcinomas and to correlate AR expression with various clinical, histopathological, and other immunohistochemical parameters. Materials and Methods  It is a cross-sectional study including 105 ER and PR Negative cases of breast carcinoma. Clinical parameters, histopathology, and immunohistochemical expression of AR, Her2, and Ki67 were analyzed in all cases. Results  AR expression was observed in 63.8% of ER and PR Negative breast cancers. In this group, AR expression was strongly associated with Her2 co-expression (89.2%) as compared to TNBCs (45.8%); p -value = 0.0002. Significant correlation was also observed between AR expression and tumor necrosis ( p -value = 0.034) and postmenopausal status ( p  = 0.007). Conclusion  Our study shows that significant proportion of ER and PR Negative breast carcinomas (ER- PR- Her2+ and TNBCs) show AR expression. We strongly recommend routine evaluation of all hormone receptor-negative breast carcinomas for AR status by immunohistochemistry.

The Prognostic Values of Androgen Receptor in Breast Cancer

CONTEXT.—

Whether androgen receptor (AR) expression can predict prognosis in breast cancer is under debate.

OBJECTIVE.—

To analyze, retrospectively, the prognostic and treatment-predictive ability of AR status in breast cancer.

DESIGN.—

A total of 5765 patients diagnosed with primary invasive breast cancer without distant metastasis in the adjuvant setting were analyzed. The propensity score-matching method was used to develop a new cohort of 3978 patients (1989 patients each) in which important prognostic factors were balanced.

RESULTS.—

Positive AR expression is an independent prognostic factor for disease-free survival and overall survival. Estrogen receptor (ER)+ and progesterone receptor (PR)+ AR+ breast cancer patients had the longest survival, whereas ER-PR-AR- breast cancer patients had the shortest survival. The ER/PR/AR combinations could not predict the treatment effects for adjuvant trastuzumab but could be used for adjuvant chemotherapy and endocrine therapy selection. The worst survival was found in ER+PR-AR- patients receiving toremifene, ER+PR-AR+ patients receiving exemestane, ER+PR+AR- patients receiving anthracycline, and ER-PR-AR+ patients receiving taxanes. ER+PR-AR-, ER-PR-AR+, and ER-PR-AR- patients were associated with the worst survival among those who received radiotherapy and anthracycline plus taxanes.

CONCLUSIONS.—

AR in combination with ER and PR could predict the prognosis and treatment effects of chemotherapy, endocrine therapy, and radiotherapy in the adjuvant setting.

Role of DEK in carcinogenesis, diagnosis, prognosis, and therapeutic outcome of breast cancer: An evidence-based clinical review

Breast cancer is a significantly burdening women's cancer with limited diagnostic modalities. DEK is a novel biomarker overexpressed in breast cancers, currently exhaustively researched for its diagnosis and prognosis. Search for relevant meta-analyses, cohorts, and experimental studies in the last fifteen years was done in five large scientific databases. Non-English, non-full text articles or unrelated studies were excluded. Thirteen articles discussed the potential of DEK to estimate breast cancer characteristics, treatment outcomes, and prognosis. This proto-oncogene plays a role in breast carcinogenesis, increasing tumour proliferation and invasion, preventing apoptosis, and creating an immunodeficient tumour milieu with M2 tumour-associated macrophages. DEK is also associated with worse clinicopathological features and survival in breast cancer patients. Using a Kaplan-Meier plotter data analysis, DEK expression predicts worse overall survival (HR 1.24, 95%CI: 1.01-1.52, p = 0.039), comparable to other biomarkers. DEK is a promising novel biomarker requiring further research to determine its bedside applications.

Prognostic Role of Androgen Receptor Expression in Surgically Resected Early Breast Cancer Patients

PURPOSE

Endocrine therapy is a standard treatment for hormone receptor-positive breast cancer, which accounts for 60%-75% of all breast cancer. Hormone receptor positivity is a prognostic and predictive biomarker in breast cancer. Approximately 50%-80% of breast cancer is also positive for androgen receptor (AR), but the prognostic and predictive value of AR expression in breast cancer is controversial. Here, we investigated AR expression and its prognostic value in patients with surgically resected breast cancer in Korea.

METHODS

We retrospectively reviewed the medical records of patients who had surgically resected breast cancer to collect AR expression data and other clinicopathological data. The optimal cut-off for AR positivity was determined using a receiver operating characteristic curve analysis.

RESULTS

We reviewed 957 patients with surgically resected breast cancer from June 2012 to April 2013. The median follow-up was 62 months, and relapse events occurred in 101 (10.6%) patients. Unlike the cut-off value of 1% or 10% in previous reports, 35% was determined to be best for predicting relapse-free survival (RFS) in this study. At the cut-off value of 35%, 654 (68.4%) patients were AR-positive. AR expression was more prevalent in luminal A (87.6%) and luminal B (73.1%) types than in human epidermal growth factor receptor 2-positive (56.2%) or triple-negative (20.6%) types. AR expression of ≥ 35% was significantly related to longer RFS in a multivariate analysis (hazard ratio, 0.430; 95% confidence interval, 0.260-0.709; p = 0.001).

CONCLUSION

We propose a cut-off value of 35% to best predict RFS in patients with surgically resected breast cancer. AR expression was positive in 68.4% of patients, and AR positivity was found to be an independent prognostic factor for longer RFS.

The estrogen receptor coactivator AIB1 is a new putative prognostic biomarker in ER-positive/HER2-negative invasive lobular carcinoma of the breast

Purpose

According to the 2017 St Gallen surrogate definitions of the intrinsic subtypes, Ki67, progesterone receptor (PR) and Nottingham histological grade (NHG) are used for prognostic classification of estrogen receptor (ER) positive/HER2-negative breast cancer into luminal A- or luminal B-like. The aim of the present study was to investigate if additional biomarkers, related to endocrine signaling pathways, e.g., amplified in breast cancer 1 (AIB1), androgen receptor (AR), and G protein-coupled estrogen receptor (GPER), can provide complementary prognostic information in a subset of ER-positive/HER-negative invasive lobular carcinoma (ILC).

Methods

Biomarkers from 224 patients were analyzed immunohistochemically on tissue microarray. The primary endpoint was breast cancer mortality (BCM), analyzed with 10- and 25-year follow-up (FU). In addition, the prognostic value of gene expression data for these biomarkers was analyzed in three publicly available ILC datasets.

Results

AIB1 (high vs. low) was associated to BCM in multivariable analysis (adjusted for age, tumor size, nodal status, NHG, Ki67, luminal-like classification, and adjuvant systemic therapy) with 10-year FU (HR 6.8, 95% CI 2.3–20, P = 0.001) and 25-year FU (HR 3.0, 95% CI 1.1–7.8, P = 0.03). The evidence of a prognostic effect of AIB1 could be confirmed by linking gene expression data to outcome in independent publicly available ILC datasets. AR and GPER were neither associated to BCM with 10-year nor with 25-year FU (P > 0.33). Furthermore, Ki67 and NHG were prognostic for BCM at both 10-year and 25-year FU, whereas PR was not.

Conclusions

AIB1 is a new putative prognostic biomarker in ER-positive/HER2-negative ILC.

Electronic supplementary material

The online version of this article (10.1007/s10549-019-05138-7) contains supplementary material, which is available to authorized users.

Androgen Receptor Inhibitor Enhances the Antitumor Effect of PARP Inhibitor in Breast Cancer Cells by Modulating DNA Damage Response

The androgen receptor (AR) is expressed in 60%-70% of breast cancers regardless of estrogen receptor status, and has been proposed as a therapeutic target in breast cancers that retain AR. In this study, the authors aimed to investigate a new treatment strategy using a novel AR inhibitor AZD3514 in breast cancer. AZD3514 alone had a minimal antiproliferative effect on most breast cancer cell lines irrespective of AR expression level, but it downregulated the expressions of DNA damage response (DDR) molecules, including ATM and chk2, which resulted in the accumulation of damaged DNA in some breast cancer cells. Furthermore, AZD3514 enhanced cellular sensitivity to a PARP inhibitor olaparib by blocking the DDR pathway in breast cancer cells. Furthermore, the downregulation of NKX3.1 expression in MDA-MB-468 cells by AZD3514 occurred in parallel with the suppression of ATM-chk2 axis activation, and the suppression of NKX3.1 by AZD3514 was found to result from AZD3514-induced TOPORS upregulation and a resultant increase in NKX3.1 degradation. The study shows posttranslational regulation of NKX3.1 via TOPORS upregulation by AZD3514-induced ATM inactivation-increased olaparib sensitivity in AR-positive and TOPORS-expressing breast cancer cells, and suggests the antitumor effect of AZD3514/olaparib cotreatment is caused by compromised DDR activity in breast cancer cell lines and in a xenograft model. These results provide a rationale for future clinical trials of olaparib/AR inhibitor combination treatment in breast cancer.

Androgen receptor and heat shock protein 27 co-regulate the malignant potential of molecular apocrine breast cancer

Background

The most striking feature of molecular apocrine breast cancer (MABC) is the expression of androgen receptor (AR). We report here the mechanism of the AR in regulating the behavior of MABC.

Methods

The MABC cell line, MDA-MB-453, and the nonMABC cell line, MCF7, were used in this study. The effect of dihydrotestosterone (DHT) and heat shock protein 27 (HSP27) on cell proliferation was quantified using the cell counter kit-8 (CCK8) and clonogenic assays in vitro and by a xenograft tumor model in vivo. The expression of the AR and HSP27 was analyzed using western blot, qPCR, and immunofluorescence assays. Complexes of the AR and HSP27 were detected by co-immunoprecipitation (Co-IP).

Results

In MDA-MB-453 cells, DHT promoted cell proliferation and stimulated AR and HSP27 translocation from the cytoplasm to the nucleus, whereas, it inhibited MCF7 cell growth, and only the AR translocated into the nucleus. HSP27 knock-down decreased the proliferative ability of MDA-MB-453 cells, which could be rescued by DHT, while HSP27 and DHT had synergistic effects on MCF7 cells. HSP27 phosphorylation was a prerequisite for AR translocation into the nucleus, especially phosphorylation on serine 82. In addition, DHT stimulated the tumorigenic and metastatic capacities of MDA-MB-453 cells, while HSP27 knock-down decreased the rate of tumor formation and induced apoptosis in cells.

Conclusions

The results suggest that HSP27 assists the AR in regulating the malignant behavior of MABC, and these findings might be helpful in the treatment of MABC.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0762-y) contains supplementary material, which is available to authorized users.

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

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

Receptor activities of persistent pollutant serum mixtures and breast cancer risk

Studies on associations between persistent organic pollutants (POPs) and breast cancer risk are inconclusive. The majority of studies have evaluated the effect of single compounds, without considering multiple exposures to and interactions between different POPs. The present study aimed at evaluating breast cancer risk related to combined effects of serum POP mixtures on cellular receptor functions. Data on breast cancer cases (n = 77) and controls (n = 84) were collected among Greenlandic Inuit women. Serum mixtures of lipophilic POPs (lipPOPs), perfluoroalkyl acids (PFAAs) and dioxin-like POPs were extracted. The effect of the mixture extracts on the estrogen receptor (ER), androgen receptor (AR) and aryl hydrocarbon receptor (AhR) was determined using cell culture reporter gene assays. The serum mixtures were analyzed alone and upon co-exposure with natural receptor ligands to determine agonistic and antagonistic/competitive activity. We found that the frequency of lipPOP mixtures eliciting no, decreasing, or agonizing xenoandrogenic effect differed by breast cancer status. Using lipPOP mixtures with no effect on AR as reference, the mixtures with decreasing effects reduced breast cancer risk (OR: 0.30 (0.12; 0.76)). The AhR-toxic equivalent of serum mixtures was significantly lower in cases than in controls, and a reduced breast cancer risk was found when comparing the third tertile to the first (OR: 0.34 (0.14; 0.83)). We found no association between the xenoestrogenic activities of lipPOPs or PFAAs and breast cancer risk. Serum lipPOP mixtures are hormone disruptive and may influence breast cancer risk, whereas PFAAs seem to influence breast cancer risk through other pathways.

Early versus late distant metastasis and adjuvant chemotherapy alone versus both radiotherapy and chemotherapy in molecular apocrine breast cancer

As a new subtype of breast cancer, molecular apocrine breast cancer (MABC) is estrogen receptor (ER) and progesterone receptor (PR) negative expression, but androgen receptor (AR) positive expression. The prognostic significance and clinical biological behavior of MABC have remained unclear up to now. This study aimed to analysis the distant metastasis behavior and response to adjuvant radiotherapy and chemotherapy of MABC subgroup. The report showed that there were significant differences between early and late distant metastasizing tumors with respect to Ki67, epidermal growth factor receptor 2 (HER2) and vascular endothelial growth factor (VEGF) expressions by a retrospective analysis consisting of 410 invasive breast cancer patients, which included 205 MABC and 205 nonMABC cases. MABC subgroup metastasized earlier than nonMABC subgroup, and MABC showed a tendency for a higher metastasis rate in lung, liver and brain, but lower in bone. HER2-positive or VEGF-positive tumors were more inclined to develop bone metastasis within MABC subgroup. The survival rate was superior for patients undergone both adjuvant radiotherapy and chemotherapy than those undergone chemotherapy alone in nonMABC subgroup, but there was no significant difference in MABC subgroup. Our data suggested that MABC subgroup seemed to develop distant metastasis earlier than nonMABC subgroup, and patients with MABC indicated poor prognosis. This study might also provide a foundation for helping patients receive reasonable treatments according to molecular subtype.

Integrated diagnostic network construction reveals a 4-gene panel and 5 cancer hallmarks driving breast cancer heterogeneity

Breast cancer encompasses a group of heterogeneous diseases, each associated with distinct clinical implications. Dozens of molecular biomarkers capable of categorizing tumors into clinically relevant subgroups have been proposed which, though considerably contribute in precision medicine, complicate our understandings toward breast cancer subtyping and its clinical translation. To decipher the networking of markers with diagnostic roles on breast carcinomas, we constructed the diagnostic networks by incorporating 6 publically available gene expression datasets with protein interaction data retrieved from BioGRID on previously identified 1015 genes with breast cancer subtyping roles. The Greedy algorithm and mutual information were used to construct the integrated diagnostic network, resulting in 37 genes enclosing 43 interactions. Four genes, FAM134B, KIF2C, ALCAM, KIF1A, were identified having comparable subtyping efficacies with the initial 1015 genes evaluated by hierarchical clustering and cross validations that deploy support vector machine and k nearest neighbor algorithms. Pathway, Gene Ontology, and proliferation marker enrichment analyses collectively suggest 5 primary cancer hallmarks driving breast cancer differentiation, with those contributing to uncontrolled proliferation being the most prominent. Our results propose a 37-gene integrated diagnostic network implicating 5 cancer hallmarks that drives breast cancer heterogeneity and, in particular, a 4-gene panel with clinical diagnostic translation potential.

Pure Apocrine Carcinomas Represent a Clinicopathologically Distinct Androgen Receptor-Positive Subset of Triple-Negative Breast Cancers

Apocrine carcinomas comprise ∼1% of all breast cancers and are characterized by large cells bearing abundant eosinophilic granular cytoplasm, round nuclei, and prominent nucleoli. They are typically estrogen receptor/progesterone receptor/HER2 negative, making them unresponsive to typical hormonal or HER2-based chemotherapy. However, this subtype of triple-negative breast cancers expresses androgen receptor (AR), a feature not shared by most nonapocrine triple-negative cancers (NA-TNCs). AR therefore represents a potential diagnostic tool and therapeutic target for apocrine breast carcinoma. All pure apocrine carcinomas diagnosed during a 10-year period were reviewed, and clinicopathologic characteristics were compared with a control group of 26 NA-TNC cases. Twenty apocrine carcinomas were identified (∼0.8% of all breast cancers). The mean age at diagnosis was 69.3 years for apocrine carcinomas and 56.7 years for NA-TNC. All apocrine carcinomas and no NA-TNC were AR positive. The proportions of apocrine carcinoma grades varied, with G1 being seen in 15% of patients, G2 in 55%, and G3 in 30%. In contrast, 100% of NA-TNC cases were G3. The majority of apocrine carcinomas presented at low T stage (T1: 70%; T2: 20%; T3: 10%; T4: 0%), whereas NA-TNC cases more often presented at T2 or higher (T1: 46.2%; T2: 30.8%; T3: 11.5%; T4: 11.5%). Thirty percent of apocrine carcinomas and 30.8% of NA-TNCs had nodal metastases at presentation. Apocrine carcinomas had a favorable clinical prognosis, with 80% of patients showing no evidence of disease-related morbidity or mortality (mean follow-up: 45.2 mo). Pure apocrine carcinomas represent a clinicopathologically distinct subgroup of triple-negative breast cancer characterized by AR positivity. When compared with NA-TNC, apocrine carcinomas more often present in older women with lower grade and T stage, a group in which a more conservative treatment regimen is often desired.

Correlation of MYC Gene and Protein Status With Breast Cancer Subtypes and Outcome of Patients Treated With Anthracycline-Based Adjuvant Chemotherapy. Pooled Analysis of 2 Hellenic Cooperative Group Phase III Trials

BACKGROUND

The prognostic/predictive value of aberrant MYC gene copies and protein expression is not clear in breast cancer.

PATIENTS AND METHODS

Early breast cancer patients were treated with anthracycline-containing chemotherapy within 2 randomized adjuvant trials. MYC gene and centromere-8 status, as well as Myc protein expression were investigated on 1060 paraffin tumors with fluorescence in situ hybridization and immunohistochemistry, respectively.

RESULTS

MYC amplification was present in 45% and polysomy-8 in 23% of the tumors. Cytoplasmic staining was observed in 60% and nuclear staining in 26% of the tumors, strongly correlating with each other but not with MYC gene status. MYC gene amplification in the absence of polysomy-8 was associated with adverse disease-free survival (DFS) and overall survival (OS), and remained as an independent unfavorable prognostic factor in multivariate analysis (Wald P = .022 for DFS; P = .032 for OS), whereas patients with MYC amplification and polysomy-8, with polysomy-8 only, and with normal MYC without polysomy-8 performed significantly better compared with those with MYC gene amplification only. Nuclear Myc protein expression benefitted patients treated with paclitaxel (interaction P = .052 for DFS; P = .049 for OS). This interaction remained independently significant in multivariate analysis for OS (overall P = .028).

CONCLUSION

The effect of MYC gene status on breast cancer patient outcome seems to depend on the underlying chromosomal instability and appears unfavorable for tumors with MYC amplification without polysomy. Nuclear Myc protein expression seems predictive for benefit from adjuvant paclitaxel. These data might aid in the interpretation of relevant findings from large clinical trials.

A review of estrogen receptor/androgen receptor genomics in male breast cancer

Male breast cancer is a rare disease, of which little is known. In contrast to female breast cancer, the very vast majority of all cases are positive for estrogen receptor alpha (ERα), implicating the function of this steroid hormone receptor in tumor development and progression. Consequently, adjuvant treatment of male breast cancer revolves around inhibition of ERα. In addition, the androgen receptor (AR) gradually receives more attention as a relevant novel target in breast cancer treatment. Importantly, the rationale of treatment decision making is strongly based on parallels with female breast cancer. Yet, prognostic indicators are not necessarily the same in breast cancer between both genders, complicating translatability of knowledge developed in female breast cancer toward male patients. Even though ERα and AR are expressed both in female and male disease, are the genomic functions of both steroid hormone receptors conserved between genders? Recent studies have reported on mutational and epigenetic similarities and differences between male and female breast cancer, further suggesting that some features are strongly conserved between the two diseases, whereas others are not. This review critically discusses the recent developments in the study of male breast cancer in relation to ERα and AR action and highlights the potential future studies to further elucidate the genomic regulation of this rare disease.

Immunohistochemical Surrogates for Molecular Classification of Breast Carcinoma: A 2015 Update

CONTEXT

-The pioneering works on molecular classification (MC) by Perou and Sorlie et al in the early 2000s using global gene expression profiling identified 5 intrinsic subtypes of invasive breast cancers (IBCs): luminal A, luminal B, normal breast-like, HER2-enriched, and basal-like subtypes, each unique in incidence, survival, and response to therapy. Because the application of gene expression profiling in daily practice is not economical or practical at the present time, many investigators have studied the use of immunohistochemical (IHC) surrogates as a substitute for determining the MC of IBC.

OBJECTIVE

-To discuss the continuing efforts that have been made to develop clinically significant and readily available IHC surrogates for the MC of IBC.

DATA SOURCES

-Data were obtained from pertinent peer-reviewed English-language literature.

CONCLUSIONS

-The most commonly used IHC surrogates are estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2), dividing IBC into luminal, HER2, and triple-negative subtypes. The addition of Ki-67, cytokeratin 5, and epidermal growth factor receptor (EGFR) separates luminal B from luminal A subtypes, and basal-like subtype from triple-negative breast cancer. More recently, biomarkers such as androgen receptor and p53 have been shown to further stratify these molecular subtypes. Although many studies of IHC-based MC have shown clinical significance similar to gene expression profiling-defined MC, its critical limitations are: (1) a lack of standardization in terminology, (2) a lack of standardization in biomarkers used for each subtype, and (3) the lack of a uniform cutoff for each biomarker. A panel of IHC surrogates for each subtype of IBC is proposed.

Molecular Testing in Breast Cancer: A Guide to Current Practices

CONTEXT

-Molecular diagnostics play a role in the management of many cancers, including breast cancer.

OBJECTIVE

-To provide an update on molecular testing in current clinical practice, targeted at practicing pathologists who are not breast cancer specialists.

DATA SOURCES

-This study is a narrative literature review.

CONCLUSIONS

-In addition to routine hormone (estrogen and progesterone) receptor testing, new and recurrent tumors are tested for HER2 amplification by in situ hybridization or overexpression by immunohistochemistry. Intrinsic subtyping of tumors represents a fundamental advance in our understanding of breast cancer biology, but currently it has an indirect role in patient management. Clinical next-generation sequencing (tumor profiling) is increasingly used to identify potentially actionable mutations in tumor tissue. Multianalyte assays with algorithmic analysis, including MammaPrint, Oncotype DX, and Prosigna, play a larger role in breast cancer than in many other malignancies. Given that a proportion of breast cancers are familial, testing of nontumor tissue for cancer predisposition mutations also plays a role in breast cancer care.

Cancer Hallmarks, Biomarkers and Breast Cancer Molecular Subtypes

Breast cancer is a complex disease encompassing multiple tumor entities, each characterized by distinct morphology, behavior and clinical implications. Besides estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, novel biomarkers have shown their prognostic and predictive values, complicating our understanding towards to the heterogeneity of such cancers. Ten cancer hallmarks have been proposed by Weinberg to characterize cancer and its carcinogenesis. By reviewing biomarkers and breast cancer molecular subtypes, we propose that the divergent outcome observed from patients stratified by hormone status are driven by different cancer hallmarks. 'Sustaining proliferative signaling' further differentiates cancers with positive hormone receptors. 'Activating invasion and metastasis' and 'evading immune destruction' drive the differentiation of triple negative breast cancers. 'Resisting cell death', 'genome instability and mutation' and 'deregulating cellular energetics' refine breast cancer classification with their predictive values. 'Evading growth suppressors', 'enabling replicative immortality', 'inducing angiogenesis' and 'tumor-promoting inflammation' have not been involved in breast cancer classification which need more focus in the future biomarker-related research. This review novels in its global view on breast cancer heterogeneity, which clarifies many confusions in this field and contributes to precision medicine.

Androgen receptor expression predicts beneficial tamoxifen response in oestrogen receptor-α-negative breast cancer

Background:

Although the androgen receptor (AR) is frequently expressed in breast cancer, its relevance in the disease is not fully understood. In addition, the relevance of AR in determining tamoxifen treatment efficiency requires evaluation.

Purpose:

To investigate the tamoxifen predictive relevance of the AR protein expression in breast cancer.

Methods

Patients were randomised to tamoxifen 40 mg daily for 2 or 5 years or to no endocrine treatment. Mean follow-up was 15 years. Hazard ratios were calculated with recurrence-free survival as end point.

Results:

In patients with oestrogen receptor (ER)-negative tumours, expression of AR predicted decreased recurrence rate with tamoxifen (hazard ratio (HR)=0.34; 95% confidence interval (CI)=0.14–0.81; P=0.015), whereas the opposite was seen in the AR− group (HR=2.92; 95% CI=1.16–7.31; P=0.022). Interaction test was significant P<0.001. Patients with triple-negative and AR+ tumours benefitted from tamoxifen treatment (HR=0.12; 95% CI=0.014–0.95 P=0.044), whereas patients with AR− tumours had worse outcome when treated with tamoxifen (HR=3.98; 95% CI=1.32–12.03; P=0.014). Interaction test was significant P=0.003. Patients with ER+ tumours showed benefit from tamoxifen treatment regardless of AR expression.

Conclusions:

AR can predict tamoxifen treatment benefit in patients with ER− tumours and triple-negative breast cancer.

Heat shock protein 27 and gross cystic disease fluid protein 15 play critical roles in molecular apocrine breast cancer

Molecular apocrine breast cancer (MABC) has a distinct hormonal profile, being estrogen receptor (ER) and progesterone receptor (PR) negative but androgen receptor (AR) positive. The clinical significance of MABC and its relative variables have not been absolutely clarified and remain to be determined. Five hundred cases of invasive breast carcinoma were randomly selected in this study, including 158 MABC cases and 342 nonMABC cases. Expression of ER, PR, epidermal growth factor receptor 2 (HER2), Ki67, AR, gross cystic disease fluid protein 15 (GCDFP15), and heat shock protein 27 (HSP27) were analyzed by immunohistochemistry. Differences of continuous variables between MABC and nonMABC subgroups were evaluated by the chi-square test. The Kaplan-Meier method was performed to evaluate disease-free survival (DFS) and overall survival (OS). The MABC subgroup had higher histological grade, bigger tumor size, more lymph node metastasis, and higher pTNM stage than the nonMABC subgroup (P < 0.05), and patients with MABC had poorer prognosis than those of the nonMABC subgroup (P < 0.05). Both GCDFP15 and HSP27 were expressed differently in the MABC and nonMABC subgroups (P < 0.05). Furthermore, in the MABC subgroup, positive HSP27 expression indicated higher risk of recurrence (P < 0.05) and positive GCDFP15 expression was also a poor marker for patient outcome (P < 0.05). MABC patients with HSP27 and GCDFP15 co-expression had worse outcome (P < 0.05). Our data suggested that MABC had a high risk of recurrence. Positive expression of both GCDFP15 and HSP27 were correlated with MABC malignancy. Targeting AR and HSP27 at the same time might offer a useful strategy to MABC.

Significance of PIK3CA Mutations in Patients with Early Breast Cancer Treated with Adjuvant Chemotherapy: A Hellenic Cooperative Oncology Group (HeCOG) Study

Background

The PI3K-AKT pathway is frequently activated in breast cancer. PIK3CA mutations are most frequently found in the helical (exon 9) and kinase (exon 20) domains of this protein. The aim of the present study was to examine the role of different types of PIK3CA mutations in combination with molecular biomarkers related to PI3K-AKT signaling in patients with early breast cancer.

Methods

Tumor tissue samples from 1008 early breast cancer patients treated with adjuvant chemotherapy in two similar randomized trials of HeCOG were examined. Tumors were subtyped with immunohistochemistry (IHC) and FISH for ER, PgR, Ki67, HER2 and androgen receptor (AR). PIK3CA mutations were analyzed by Sanger sequencing (exon 20) and qPCR (exon 9) (Sanger/qPCR mutations). In 610 cases, next generation sequencing (NGS) PIK3CA mutation data were also available. PIK3CA mutations and PTEN protein expression (IHC) were analyzed in luminal tumors (ER and/or PgR positive), molecular apocrine carcinomas (MAC; ER/PgR negative / AR positive) and hormone receptor (ER/PgR/AR) negative tumors.

Results

PIK3CA mutations were detected in 235/1008 tumors (23%) with Sanger/qPCR and in 149/610 tumors (24%) with NGS. Concordance between the two methods was good with a Kappa coefficient of 0.76 (95% CI 0.69–0.82). Lobular histology, low tumor grade and luminal A tumors were associated with helical domain mutations (PIK3CAhel), while luminal B with kinase domain mutations (PIK3CAkin). The overall incidence of PIK3CA mutations was higher in luminal as compared to MAC and hormone receptor negative tumors (p = 0.004). Disease-free and overall survival did not significantly differ with respect to PIK3CA mutation presence and type. However, a statistically significant interaction between PIK3CA mutation status and PTEN low protein expression with regard to prognosis was identified.

Conclusions

The present study did not show any prognostic significance of specific PIK3CA mutations in a large group of predominantly lymph-node positive breast cancer women treated with adjuvant chemotherapy. Further analyses in larger cohorts are warranted to investigate possible differential effect of distinct PIK3CA mutations in small subgroups of patients.

FABP7 and HMGCS2 are novel protein markers for apocrine differentiation categorizing apocrine carcinoma of the breast

Apocrine carcinoma of the breast is a distinctive malignancy with unique morphological and molecular features, generally characterized by being negative for estrogen and progesterone receptors, and thus not electable for endocrine therapy. Despite the fact that they are morphologically distinct from other breast lesions, no standard molecular criteria are currently available for their diagnosis. Using gel-based proteomics in combination with mass spectrometry and immunohistochemistry we have identified two novel markers, HMGCS2 and FABP7 that categorize the entire breast apocrine differentiation spectrum from benign metaplasia and cysts to invasive stages. Expression of HMGCS2 and FABP7 is strongly associated with apocrine differentiation; their expression is retained by most invasive apocrine carcinomas (IAC) showing positive immunoreactivity in 100% and 78% of apocrine carcinomas, respectively, as compared to non-apocrine tumors (16.7% and 6.8%). The nuclear localization of FABP7 in tumor cells was shown to be associated with more aggressive stages of apocrine carcinomas. In addition, when added to the panel of apocrine biomarkers previously reported by our group: 15-PGDH, HMGCR and ACSM1, together they provide a signature that may represent a golden molecular standard for defining the apocrine phenotype in the breast. Moreover, we show that combining HMGCS2 to the steroidal profile (HMGCS2+/Androgen Receptor (AR)+/Estrogen Receptor(ER)-/Progesteron Receptor (PR)- identifies IACs with a greater sensitivity (79%) as compared with the steroidal profile (AR+/ER-/PR-) alone (54%). We have also presented a detailed immunohistochemical analysis of breast apocrine lesions with a panel of antibodies against proteins which correspond to 10 genes selected from published transcriptomic signatures that currently characterize molecular apocrine subtype and shown that except for melanophilin that is overexpressed in benign apocrine lesions, these proteins were not specific for morphological apocrine differentiation in breast.