The clinicopathologic features of molecular apocrine breast cancer

Triple-negative apocrine carcinoma: A rare pathologic subtype with a better prognosis than other triple-negative breast cancers

BACKGROUND AND METHODS

Apocrine adenocarcinoma is a rare subtype of breast cancer. We sought to compare the characteristics and survival of patients diagnosed with triple-negative apocrine adenocarcinoma to those of patients diagnosed with triple-negative invasive ductal carcinoma. Utilizing data from the National Cancer Database between 2004 and 2013, 70 524 eligible female patients with triple-negative breast cancer were identified including 566 patients with apocrine adenocarcinomas and 69 958 patients with invasive ductal carcinoma. Descriptive statistics for each variable were reported. A comparison of each covariate between the study cohorts was assessed in univariate and multivariate analysis. Cox proportional models were used to calculate hazard ratios. Additionally, the propensity score matching method was implemented to reduce treatment selection bias.

RESULTS

Patients with triple-negative apocrine tumors were more likely to be older, Caucasian, and have smaller, moderately to well-differentiated tumors. Multivariable analysis noted a significantly improved survival for patients with triple-negative apocrine carcinoma (TNAC) vs triple-negative invasive ductal carcinoma (TNBC) (hazard ratio [HR] 0.65 [95% confidence interval [CI] [0.53-0.81], P = 0 < .001). Propensity score matching analysis confirmed a significant difference in overall survival for patients with TNAC in comparison to TNBC (HR 0.79 [95% CI [0.63-1.00], P = .05).

DISCUSSION

Triple-negative apocrine adenocarcinomas have a modestly improved long-term survival when compared with triple-negative invasive ductal cancers.

[Androgen receptor-positive triple negative breast cancer: From biology to therapy]

A subgroup of androgen receptor-expressing tumors represents approximately 30 % of all triple negative tumors. The androgen receptor and its signaling pathways have a central biological role in this tumor entity. These triple negative androgen receptor-positive tumors occur in older patients and do not appear to have a better prognosis compared to other triple negative tumors. In addition to androgen receptor-expression, these tumors are genomically characterized by a high frequency of PIK3CA activating mutation. Three clinical trials reported efficacy data for anti-androgens (bicalutamide, abiraterone acetate and enzalutamide) based on strong preclinical rationale. These trials report clinical benefit rates in about one in five patients. These encouraging but still limited results make a case for the identification of predictive response factors and therapeutic combinations to improve response rates. This review will provide an update on the biological and clinical knowledge of this tumoral subgroup that opens the way to non-cytotoxic anti-androgen therapies.

The role of histopathologic testing on apocrine carcinoma of the breast

BACKGROUND

Apocrine carcinoma is a rare primary breast tumor characterized by the apocrine morphology. The purpose of this article is to report a review of cases with apocrine carcinoma and draw physicians' attention to the benefits of immunphenotypic techniques in cases with suspected apocrine morphology in diagnosing this uncommon breast tumor.

METHODS

In this study, authors report a case series of 15 cases with apocrine carcinoma from totally 4123 breast cancer cases. Data collected between years 2008 and 2016 from Istanbul School of Medicine department of surgery archive by analyzing surgical approach to cases and immunphenotypic features of tumors according to the date of examining in our pathology department.

RESULTS

In this study, Androgen, "gross cystic disease fluid protein-15" (GCDFP-15), estrogen (ER), progesterone (PR) and Her-2 neu receptor status supported evidence of apocrine carcinoma has been reviewed. As a result, HER-2 neu, GCDFP-15, androgen receptor positivity in general are useful in the diagnosis of apocrine carcinoma. In addition of these data our study revealed that GCDFP-15 positive patients are more prone to have local recurrence and distant metastases.

CONCLUSIONS

We briefly describe and discuss the molecular features and new diagnostic biomarkers for this rare mammary malignancy. The importance of comprehensive profiling is highlighted due to synergistic and potentially antagonistic molecular events in the individual patients.

Apocrine lesions of the breast: part 2 of a two-part review. Invasive apocrine carcinoma, the molecular apocrine signature and utility of immunohistochemistry in the diagnosis of apocrine lesions of the breast

Pure apocrine carcinoma of the breast is rare and has been defined by using a combination of morphologic (apocrine morphology in >90% of tumour cells) and immunohistochemical criteria (oestrogen receptor (ER) and progesterone receptor (PR) negative and androgen receptor (AR) positive). Recent advances in the molecular classification of breast tumours have uncovered a subset of breast tumours associated with high expression of androgen receptor mRNA including the so-called 'luminal androgen receptor (LAR) tumours' and 'molecular apocrine tumours' (MATs). Recognition of these tumour subsets has opened potential avenues for therapies exploiting the AR pathway in triple negative breast carcinoma (TNBC). In this second part of our two-part review, we focus on the definition of pure apocrine carcinoma, recent advances in understanding the molecular apocrine signature in breast carcinoma, its relationship to pure apocrine carcinoma defined at the level of light microscopy and immunohistochemistry (IHC) and the therapeutic implications of androgen expression in TNBC. We complete the article with a summary of the utility of IHC in stratifying apocrine lesions of the breast.

Enhancing Abiraterone Acetate Efficacy in Androgen Receptor-positive Triple-negative Breast Cancer: Chk1 as a Potential Target

PURPOSE

Our aim was to identify predictive factors of abiraterone acetate efficacy and putative new druggable targets in androgen receptor (AR)-positive triple-negative breast cancer (TNBC) treated in the UCBG 2012-1 trial.Experimental Design: We defined abiraterone acetate response as either complete or partial response, or stable disease at 6 months. We sequenced 91 general and breast cancer-associated genes from the tumor DNA samples. We analyzed transcriptomes from the extracted RNA samples on a NanoString platform and performed IHC using tissue microarrays. We assessed abiraterone acetate and Chk1 inhibitors (GDC-0575 and AZD7762) efficacies, either alone or in combination, on cell lines grown in vitro and in vivo.

RESULTS

Classic IHC apocrine markers including AR, FOXA1, GGT1, and GCDFP15, from patients' tumors allowed identifying abiraterone acetate-responders and nonresponders. All responders had clear apocrine features. Transcriptome analysis revealed that 31 genes were differentially expressed in the two subgroups, 9 of them being linked to proliferation and DNA damage repair. One of the most significant differences was the overexpression, in nonresponders, of CHEK1, a gene encoding Chk1, a protein kinase that can be blocked by specific inhibitors. On the basis of cell line experiments, abiraterone acetate and Chk1 inhibitor combination showed at least additive effect on cell viability, cell cycle, apoptosis, and accumulation of DNA damages. In vivo, orthotopic xenograft experiments confirmed the efficacy of this combination therapy.

CONCLUSIONS

This study suggests that apocrine features can be helpful in the identification of abiraterone acetate-responders. We identified Chk1 as a putative drug target in AR-positive TNBCs.

Dose invasive apocrine adenocarcinoma has worse prognosis than invasive ductal carcinoma of breast: evidence from SEER database

Background

Invasive apocrine adenocarcinoma (AAC) of breast is a rare histopathological subtype of breast carcinomas. We aim to investigate the different characteristics and prognostic outcomes between AAC and invasive ductal carcinoma (IDC) of breast cancer.

RESULTS

AAC patients presented with older ages, more aggressive behaviors, lower ER and PR proportions, higher HER2 amplification rates and less application of breast-conserving therapy and adjuvant chemotherapy compared to IDC patients. Long-term OS and DSS were both worse in ACC patients (p = 0.006, p = 0.012 respectively) than in IDC patients by Kaplan-Meier analysis. However, no significant difference was detected in DSS (p = 0.181) and OS (p = 0.116) between the matched two histological subtypes. Further subgroup analysis indicated that AJCC stage, ER status, PR status and HER2 status may be principal confounders for AAC prognosis.

Materials and Methods

With accession to the Surveillance, Epidemiology and End Result (SEER) database, a total of 260,596 patients met the eligibility criteria. Clinicopathological characteristics were compared between groups using Chi-square test. Univariate and multivariate analyses were applied to evaluate the overall survival (OS) and disease-specific survival (DSS). Subgroup analyses summarized the hazard ratio (HR) of AAC versus IDC using a forest plot.

Conclusions

AAC had unique clinicopathological characteristics and it tended to be a more aggressive type than IDC. However, the worse prognosis was diminished after matching for demographic and clinicopathological factors. Deeper insights into AAC are in need to contribute to individualized and tailored therapy, which thereby may improve clinical management and outcomes.

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.

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.

Androgen Receptor: A Complex Therapeutic Target for Breast Cancer

Molecular and histopathological profiling have classified breast cancer into multiple sub-types empowering precision treatment. Although estrogen receptor (ER) and human epidermal growth factor receptor (HER2) are the mainstay therapeutic targets in breast cancer, the androgen receptor (AR) is evolving as a molecular target for cancers that have developed resistance to conventional treatments. The high expression of AR in breast cancer and recent discovery and development of new nonsteroidal drugs targeting the AR provide a strong rationale for exploring it again as a therapeutic target in this disease. Ironically, both nonsteroidal agonists and antagonists for the AR are undergoing clinical trials, making AR a complicated target to understand in breast cancer. This review provides a detailed account of AR’s therapeutic role in breast cancer.

HER2 status in molecular apocrine breast cancer: associations with clinical, pathological, and molecular features

Molecular apocrine breast cancer (MABC) is a distinct subtype of breast cancer. The purpose of this study was to investigate the relationship between HER2 status and clinicopathologic characteristics of MABCs from Chinese Han cohort. A cohort of 90 MABC patients were enrolled. Immunohistochemical method was performed to analyze the molecular expression, and the human epidermal growth factor receptor 2 (HER2) amplification was verified by fluorescence in situ hybridization (FISH). By studying these 90 MABC cases, the majority of studied patients were premenopausal young women (median age 48 yr) with high grade tumors. We also found that MABCs had high positive expression rates of HER2, CK8, CD44, CD166, p53 and BRCA1, the elevated Ki-67 labeling index, and favorable prognosis. There was a significantly higher incidence of lymph node metastasis and lower CD166 positive rate in HER2-negative patients compared to HER2-positive patients (54.5% vs. 37.0%, P = 0.044 and 72.7% vs. 91.3%, P = 0.021, respectively). The CK5/6 and EGFR expression rates were significant higher in HER2-negative cases than in HER2-positive cases, suggesting that there is overlap between MABC with HER2-negative phenotype and basal-like breast cancer. In addition, HER2 positive was found to be significantly associated a poor overall survival in MABCs. In conclusion, HER2 are highly expressed, and HER2 positivity could be considered as a significant biomarker of poor prognosis in MABC. The results also suggest that a subtype tumor with distinct patterns of molecule expression depending on HER2 status presented in MABC.