The Genomic Landscape of Male Breast Cancers

Male breast cancer differs from female breast cancer in molecular features that affect prognoses and drug responses

BACKGROUND

Male breast cancer (MBC) is a rare malignancy with a worse prognosis than female breast cancer (FBC). Current MBC treatment strategies are based on those for FBC. However, molecular differences between MBC and FBC with respect to prognosis and drug responses remain unclear.

METHODS

After controlling for confounding factors with propensity score matching (PSM), differences between MBC and FBC were comprehensively analyzed using many types of data: survival, immune microenvironments, sex hormone responses, drug sensitivity, transcriptomes, genomes, epigenomes, and proteomes.

RESULTS

Overall survival (OS) and cancer-specific survival (CSS) were both worse for MBC than for FBC. Differentially expressed mRNAs were enriched in numerous cancer-related functions and pathways, with SPAG16 and STOX1 being as the most important prognosis-related mRNAs for MBC. Competing endogenous RNA (ceRNA) and transcription factor (TF)-mRNA regulatory networks contain potential prognostic genes. Nine genes had higher mutation frequencies in MBC than in FBC. MBC shows a comparatively poor response to immunotherapy, with five proteins that promote breast cancer progression being highly expressed in MBC. MBC may be more responsive than FBC to estrogen. We detected six United States Food and Drug Administration (FDA)-approved therapeutic target genes as being differentially expressed between MBC and FBC.

CONCLUSION

The poor prognosis of MBC compared to FBC is due to numerous molecular differences and resulting drug responses.

Exploring the One Health Paradigm in Male Breast Cancer

How cancer patterns in humans compare to those of other species remains largely unknown and there is an even bigger knowledge gap for rare cancers like male breast cancer. One Health is a convergence of human and animal healthcare that encourages cross-pollination of medical research uniting human and veterinary medicine. Recognising that breast cancer occurs spontaneously in other male species (e.g. primates, canines, felines), and knowing that no laboratory models exist for male breast cancer, which limits our ability to perform functional studies, we explored the feasibility of applying One Health to breast cancer in men by conducting a narrative review of the topic. Spontaneous development of breast cancer was reported in captive male primates and in companion canines and felines. Some parallels in tumour biology of human male breast cancer with canines and primates were found. The age distribution, pattern of biomarker expression and metastasis were similar, with mammary tumours typically detected after two-thirds of average lifespan. However, instances of triple negative and inflammatory breast cancer, which are rarely observed in human male breast cancer, were found in canines and histological classification was inconsistent between species. These disparities need redressing to enable full exploration of the One Health paradigm in rare cancers.

Whole-Genome Sequencing Analysis of Male Breast Cancer Unveils Novel Structural Events and Potential Therapeutic Targets

The molecular characterization of male breast cancer (MaBC) has received limited attention in research, mostly because of its low incidence rate, accounting for only 0.5% to 1% of all reported cases of breast cancer each year. Managing MaBC presents significant challenges, with most treatment protocols being adapted from those developed for female breast cancer. Utilizing whole-genome sequencing (WGS) and state-of-the-art analyses, the genomic features of 10 MaBC cases (n = 10) were delineated and correlated with clinical and histopathologic characteristics. Using fluorescence in situ hybridization, an additional cohort of 18 patients was interrogated to supplement WGS findings. The genomic landscape of MaBC uncovered significant genetic alterations that could influence diagnosis and treatment. We found common somatic mutations in key driver genes, such as FAT1, GATA3, SMARCA4, and ARID2. Our study also mapped out structural variants that impact cancer-associated genes, such as ARID1A, ESR1, GATA3, NTRK1, and NF1. Using a WGS-based classifier, homologous recombination deficiency (HRD) was identified in 2 cases, both presenting with deleterious variants in BRCA2. Noteworthy was the observation of FGFR1 amplification in 21% of cases. Altogether, we identified at least 1 potential therapeutic target in 8 of the 10 cases, including high tumor mutational burden, FGFR1 amplification, and HRD. Our study is the first WGS characterization of MaBC, which uncovered potentially relevant variants, including structural events in cancer genes, HRD signatures, and germline pathogenic mutations. Our results demonstrate unique genetic markers and potential treatment targets in MaBC, thereby underlining the necessity of tailoring treatment strategies for this understudied patient population. These WGS-based findings add to the growing knowledge of MaBC genomics and highlight the need to expand research on this type of cancer.

Gender-Specific Genetic Predisposition to Breast Cancer: BRCA Genes and Beyond

Among neoplastic diseases, breast cancer (BC) is one of the most influenced by gender. Despite common misconceptions associating BC as a women-only disease, BC can also occur in men. Additionally, transgender individuals may also experience BC. Genetic risk factors play a relevant role in BC predisposition, with important implications in precision prevention and treatment. The genetic architecture of BC susceptibility is similar in women and men, with high-, moderate-, and low-penetrance risk variants; however, some sex-specific features have emerged. Inherited high-penetrance pathogenic variants (PVs) in BRCA1 and BRCA2 genes are the strongest BC genetic risk factor. BRCA1 and BRCA2 PVs are more commonly associated with increased risk of female and male BC, respectively. Notably, BRCA-associated BCs are characterized by sex-specific pathologic features. Recently, next-generation sequencing technologies have helped to provide more insights on the role of moderate-penetrance BC risk variants, particularly in PALB2, CHEK2, and ATM genes, while international collaborative genome-wide association studies have contributed evidence on common low-penetrance BC risk variants, on their combined effect in polygenic models, and on their role as risk modulators in BRCA1/2 PV carriers. Overall, all these studies suggested that the genetic basis of male BC, although similar, may differ from female BC. Evaluating the genetic component of male BC as a distinct entity from female BC is the first step to improve both personalized risk assessment and therapeutic choices of patients of both sexes in order to reach gender equality in BC care. In this review, we summarize the latest research in the field of BC genetic predisposition with a particular focus on similarities and differences in male and female BC, and we also discuss the implications, challenges, and open issues that surround the establishment of a gender-oriented clinical management for BC.

Unfolding the role of the PI3K/AKT/MTOR pathway in male breast cancer: A pragmatic appraisal

Breast cancer in men is rare, but a relevant public health issue, yielding a 25% higher risk of mortality comparing to female counterparts. The representation of males in clinical trials has been scarce and treatment decisions are based mainly on extrapolations from data in females. In the setting of estrogen-dependent metastatic disease, the use of everolimus has been seldom reported, although the PI3K/AKT/mTOR pathway seems to be a critical oncogenic driver. This paper dissects hallmark biological features of ER+/HER2-advanced male breast cancer, setting a comprehensive basis to promote personalized care, focusing on the potential of targeting the PI3K/AKT/mTOR pathway.

Population-specific Mutation Patterns in Breast Tumors from African American, European American, and Kenyan Patients

Women of African descent have the highest breast cancer mortality in the United States and are more likely than women from other population groups to develop an aggressive disease. It remains uncertain to what extent breast cancer in Africa is reminiscent of breast cancer in African American or European American patients. Here, we performed whole-exome sequencing of genomic DNA from 191 breast tumor and non-cancerous adjacent tissue pairs obtained from 97 African American, 69 European American, 2 Asian American, and 23 Kenyan patients. Our analysis of the sequencing data revealed an elevated tumor mutational burden in both Kenyan and African American patients, when compared with European American patients. TP53 mutations were most prevalent, particularly in African American patients, followed by PIK3CA mutations, which showed similar frequencies in European American, African American, and the Kenyan patients. Mutations targeting TBX3 were confined to European Americans and those targeting the FBXW7 tumor suppressor to African American patients whereas mutations in the ARID1A gene that are known to confer resistance to endocrine therapy were distinctively enriched among Kenyan patients. A Kyoto Encyclopedia of Genes and Genomes pathway analysis could link FBXW7 mutations to an increased mitochondrial oxidative phosphorylation capacity in tumors carrying these mutations. Finally, Catalogue of Somatic Mutations in Cancer (COSMIC) mutational signatures in tumors correlated with the occurrence of driver mutations, immune cell profiles, and neighborhood deprivation with associations ranging from being mostly modest to occasionally robust. To conclude, we found mutational profiles that were different between these patient groups. The differences concentrated among genes with low mutation frequencies in breast cancer.

SIGNIFICANCE

The study describes differences in tumor mutational profiles between African American, European American, and Kenyan breast cancer patients. It also investigates how these profiles may relate to the tumor immune environment and the neighborhood environment in which the patients had residence. Finally, it describes an overrepresentation of ARID1A gene mutations in breast tumors of the Kenyan patients.

Axillary Lymph Node Dissection is Associated with Improved Survival Among Men with Invasive Breast Cancer and Sentinel Node Metastasis

BACKGROUND

Male breast cancer (MBC) is rare, and management is extrapolated from trials that enroll only women. It is unclear whether contemporary axillary management based on data from landmark trials in women may also apply to men with breast cancer. This study aimed to compare survival in men with positive sentinel lymph nodes after sentinel lymph node biopsy (SLNB) alone versus complete axillary dissection (ALND).

PATIENTS AND METHODS

Using the National Cancer Database, men with clinically node-negative, T1 and T2 breast cancer and 1-2 positive sentinel nodes who underwent SLNB or ALND were identified from 2010 to 2020. Both 1:1 propensity score matching and multivariate regression were used to identify patient and disease variables associated with ALND versus SLNB. Survival between ALND and SLNB were compared using Kaplan-Meier methods.

RESULTS

A total of 1203 patients were identified: 61.1% underwent SLNB alone and 38.9% underwent ALND. Treatment in academic centers (36.1 vs. 27.7%; p < 0.0001), 2 positive lymph nodes on SLNB (32.9 vs. 17.3%, p < 0.0001) and receipt or recommendation of chemotherapy (66.5 vs. 52.2%, p < 0.0001) were associated with higher likelihood of ALND. After propensity score matching, ALND was associated with superior survival compared with SLNB (5-year overall survival of 83.8 vs. 76.0%; log-rank p = 0.0104).

DISCUSSION

The results of this study suggest that among patients with early-stage MBC with limited sentinel lymph node metastasis, ALND is associated with superior survival compared with SLNB alone. These findings indicate that it may be inappropriate to extrapolate the results of the ACOSOG Z0011 and EORTC AMAROS trials to MBC.

Single-Cell Transcriptional and Epigenetic Profiles of Male Breast Cancer Nominate Salient Cancer-Specific Enhancers

Male breast cancer represents about 1% of all breast cancer diagnoses and, although there are some similarities between male and female breast cancer, the paucity of data available on male breast cancer makes it difficult to establish targeted therapies. To date, most male breast cancers (MBCs) are treated according to protocols established for female breast cancer (FBC). Thus, defining the transcriptional and epigenetic landscape of MBC with improved resolution is critical for developing better avenues for therapeutic intervention. In this study, we present matched transcriptional (scRNA-seq) and epigenetic (scATAC-seq) profiles at single-cell resolution of two treatment naïve MBC tumors processed immediately after surgical resection. These data enable the detection of differentially expressed genes between male and female breast tumors across immune, stromal, and malignant cell types, to highlight several genes that may have therapeutic implications. Notably, MYC target genes and mTORC1 signaling genes were significantly upregulated in the malignant cells of MBC compared to the female counterparts. To understand how the regulatory landscape of MBC gives rise to these male-specific gene expression patterns, we leveraged the scATAC-seq data to systematically link changes in chromatin accessibility to changes in gene expression within each cell type. We observed cancer-specific rewiring of several salient enhancers and posit that these enhancers have a higher regulatory load than lineage-specific enhancers. We highlight two examples of previously unannotated cancer-cell-specific enhancers of ANXA2 and PRDX4 gene expression and show evidence for super-enhancer regulation of LAMB3 and CD47 in male breast cancer cells. Overall, this dataset annotates clinically relevant regulatory networks in male breast tumors, providing a useful resource that expands our current understanding of the gene expression programs that underlie the biology of MBC.

Copy number variations in male breast cancer

Common copy number variations often contain cancer-related genes and are likely to play a role in carcinogenesis. Different mechanisms of tumorigenesis are suggested in female and male breast cancer because of different molecular profiles. The cytogenetic analysis of GTG-banded chromosomes was performed in six male patients with infiltrating ductal carcinoma and six healthy male controls matched for age. Single-nucleotide polymorphism (SNP) array analysis was performed in male breast cancer (MBC) patients. Cytogenetic analysis found aberrations previously implicated in cancer. SNP array analysis in patients revealed a gain of Xp11.23, 8p23.2, Yq11.221, Yq11.3 (AZF region), 12p11.21, 18q12.1, and 17q21.3; a loss of Yq11.222 and 7q11.21; and a loss of heterozygosity of 4p16.3, 6p12.3, 6p22.2-p21.31, 7p14.2-14.1, 18q11.2-q12.1, 20p11.23-11.1, 20q11.21-11.23, 1q25.2-q25.3, 2q11.1-q11.2, 5q23.1-23.2, 11p15.4-15.3, and 22q13.1-13.31. Some of these variations, especially those of the Y-chromosome, have not been reported earlier. Chromosomal loci identified by SNP array harbor genes were reported to be associated with cancer progression and metastasis, indicating their involvement in MBC also.

The prediction of distant metastasis risk for male breast cancer patients based on an interpretable machine learning model

OBJECTIVES

This research was designed to compare the ability of different machine learning (ML) models and nomogram to predict distant metastasis in male breast cancer (MBC) patients and to interpret the optimal ML model by SHapley Additive exPlanations (SHAP) framework.

METHODS

Four powerful ML models were developed using data from male breast cancer (MBC) patients in the SEER database between 2010 and 2015 and MBC patients from our hospital between 2010 and 2020. The area under curve (AUC) and Brier score were used to assess the capacity of different models. The Delong test was applied to compare the performance of the models. Univariable and multivariable analysis were conducted using logistic regression.

RESULTS

Of 2351 patients were analyzed; 168 (7.1%) had distant metastasis (M1); 117 (5.0%) had bone metastasis, and 71 (3.0%) had lung metastasis. The median age at diagnosis is 68.0 years old. Most patients did not receive radiotherapy (1723, 73.3%) or chemotherapy (1447, 61.5%). The XGB model was the best ML model for predicting M1 in MBC patients. It showed the largest AUC value in the tenfold cross validation (AUC:0.884; SD:0.02), training (AUC:0.907; 95% CI: 0.899-0.917), testing (AUC:0.827; 95% CI: 0.802-0.857) and external validation (AUC:0.754; 95% CI: 0.739-0.771) sets. It also showed powerful ability in the prediction of bone metastasis (AUC: 0.880, 95% CI: 0.856-0.903 in the training set; AUC: 0.823, 95% CI:0.790-0.848 in the test set; AUC: 0.747, 95% CI: 0.727-0.764 in the external validation set) and lung metastasis (AUC: 0.906, 95% CI: 0.877-0.928 in training set; AUC: 0.859, 95% CI: 0.816-0.891 in the test set; AUC: 0.756, 95% CI: 0.732-0.777 in the external validation set). The AUC value of the XGB model was larger than that of nomogram in the training (0.907 vs 0.802) and external validation (0.754 vs 0.706) sets.

CONCLUSIONS

The XGB model is a better predictor of distant metastasis among MBC patients than other ML models and nomogram; furthermore, the XGB model is a powerful model for predicting bone and lung metastasis. Combining with SHAP values, it could help doctors intuitively understand the impact of each variable on outcome.

PipeIT2: A tumor-only somatic variant calling workflow for molecular diagnostic Ion Torrent sequencing data

Precision oncology relies on the accurate identification of somatic mutations in cancer patients. While the sequencing of the tumoral tissue is frequently part of routine clinical care, the healthy counterparts are rarely sequenced. We previously published PipeIT, a somatic variant calling workflow specific for Ion Torrent sequencing data enclosed in a Singularity container. PipeIT combines user-friendly execution, reproducibility and reliable mutation identification, but relies on matched germline sequencing data to exclude germline variants. Expanding on the original PipeIT, here we describe PipeIT2 to address the clinical need to define somatic mutations in the absence of germline control. We show that PipeIT2 achieves a > 95% recall for variants with variant allele fraction >10%, reliably detects driver and actionable mutations and filters out most of the germline mutations and sequencing artifacts. With its performance, reproducibility, and ease of execution, PipeIT2 is a valuable addition to molecular diagnostics laboratories.

Molecular profiling of male breast cancer by multigene panel testing: Implications for precision oncology

Introduction

Compared with breast cancer (BC) in women, BC in men is a rare disease with genetic and molecular peculiarities. Therapeutic approaches for male BC (MBC) are currently extrapolated from the clinical management of female BC, although the disease does not exactly overlap in males and females. Data on specific molecular biomarkers in MBC are lacking, cutting out male patients from more appropriate therapeutic strategies. Growing evidence indicates that Next Generation Sequencing (NGS) multigene panel testing can be used for the detection of predictive molecular biomarkers, including Tumor Mutational Burden (TMB) and Microsatellite Instability (MSI).

Methods

In this study, NGS multigene gene panel sequencing, targeting 1.94 Mb of the genome at 523 cancer-relevant genes (TruSight Oncology 500, Illumina), was used to identify and characterize somatic variants, Copy Number Variations (CNVs), TMB and MSI, in 15 Formalin-Fixed Paraffin-Embedded (FFPE) male breast cancer samples.

Results and discussion

A total of 40 pathogenic variants were detected in 24 genes. All MBC cases harbored at least one pathogenic variant. PIK3CA was the most frequently mutated gene, with six (40.0%) MBCs harboring targetable PIK3CA alterations. CNVs analysis showed copy number gains in 22 genes. No copy number losses were found. Specifically, 13 (86.7%) MBCs showed gene copy number gains. MYC was the most frequently amplified gene with eight (53.3%) MBCs showing a median fold-changes value of 1.9 (range 1.8-3.8). A median TMB value of 4.3 (range 0.8-12.3) mut/Mb was observed, with two (13%) MBCs showing high-TMB. The median percentage of MSI was 2.4% (range 0-17.6%), with two (13%) MBCs showing high-MSI. Overall, these results indicate that NGS multigene panel sequencing can provide a comprehensive molecular tumor profiling in MBC. The identification of targetable molecular alterations in more than 70% of MBCs suggests that the NGS approach may allow for the selection of MBC patients eligible for precision/targeted therapy.

Clinicopathological features, genetic alterations, and BRCA1 promoter methylation in Japanese male patients with breast cancer

PURPOSE

Male breast cancer (MBC) is a rare cancer accounting for only 1% of all male cancers and is, therefore, poorly studied. We aimed to characterize the subtypes of MBC in Japanese patients based on genetic profiling, the presence of tumor-infiltrating cells, and the expression of immunohistochemical markers.

METHODS

This retrospective study included 103 patients with MBC diagnosed between January 2009 and December 2019 at various hospitals in Japan. Clinicopathological patient characteristics were obtained from medical records, and formalin-fixed paraffin-embedded tissue specimens were analyzed for histological markers, mutations of 126 genes, BRCA1 methylation, and stromal tumor-infiltrating lymphocytes.

RESULTS

The median patient age was 71 (range 31-92) years. T1-stage tumors were the most frequent (47.6%), and most were node negative (77.7%). The majority of tumors were positive for estrogen receptor (98.1%), progesterone receptor (95.1%), and androgen receptor (96.1%), and BRCA2 was the most frequently mutated gene (12.6%). The most common treatment was surgery (99.0%), either total mastectomy (91.1%) or partial mastectomy (7.0%). Survival analysis showed a 5-year recurrence-free survival rate of 64.4% (95% confidence interval [CI] 46.7-88.8) and a 5-year overall survival rate of 54.3% (95% CI 24.1-100.0).

CONCLUSION

Japanese MBC is characterized by a high rate of hormonal receptor positivity and BRCA2 somatic mutation. Due to the observed clinicopathological differences in MBC between the Western countries and Japan, further prospective studies are needed to evaluate the most suitable treatment strategies.

Novel markers in breast pathology

Breast pathology is an ever-expanding database of information which includes markers, or biomarkers, that detect or help treat the disease as prognostic or predictive information. This review focuses on these aspects of biomarkers which are grounded in immunohistochemistry, liquid biopsies and next-generation sequencing.

Impacts of Subtype on Clinical Feature and Outcome of Male Breast Cancer: Multicenter Study in Korea (KCSG BR16-09)

PURPOSE

The treatment of male breast cancer (MBC) has been extrapolated from female breast cancer (FBC) because of its rarity despite their different clinicopathologic characteristics. We aimed to investigate the distribution of intrinsic subtypes based on immunohistochemistry, their clinical impact, and treatment pattern in clinical practice through a multicenter study in Korea.

MATERIALS AND METHODS

We retrospectively analyzed clinical data of 248 MBC patients from 18 institutions across the country from January 1995 to July 2016.

RESULTS

The median age of MBC patients was 63 years (range, 25 to 102 years). Among 148 intrinsic subtype classified patients, 61 (41.2%), 44 (29.7%), 29 (19.5%), and 14 (9.5%) were luminal A, luminal B, human epidermal growth factor receptor 2, and triple-negative breast cancer, respectively. Luminal A subtype showed trends for superior survival compared to other subtypes. Most hormone receptor-positive patients (166 patients, 82.6%) received adjuvant endocrine treatment. Five-year completion of adjuvant endocrine treatment was associated with superior disease-free survival (DFS) in patients classified with an intrinsic subtype (hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04 to 0.49; p=0.002) and in all patients (HR, 0.16; 95% CI, 0.05 to 0.54; p=0.003).

CONCLUSION

Distribution of subtypes of MBC was similar to FBC and luminal type A was most common. Overall survival tended to be improved for luminal A subtype, although there was no statistical significance. Completion of adjuvant endocrine treatment was associated with prolonged DFS in intrinsic subtype classified patients. MBC patients tended to receive less treatment. MBC patients should receive standard treatment according to guidelines as FBC patients.

Controversies and Opportunities in the Clinical Daily Use of the 21-Gene Assay for Prognostication and Prediction of Chemotherapy Benefit in HR+/HER2- Early Breast Cancer

Several multigene assays have been developed to help clinicians in defining adjuvant treatment for patients with hormone-receptor-positive (HR+), human epidermal growth factor receptor-2 (HER2)-negative early breast cancer. Despite the 21-gene assay having been available for decades, it has only recently been included in the healthcare systems of several countries. Clinical optimisation of the test remains of critical interest to achieve a greater impact of genomic information in HR+/HER2- early breast cancer. Although current guidelines recommend the use of the 21-gene assay in early breast cancer at intermediate risk of relapse, the implication of the Recurrence Score (RS) in some grey areas still remains uncertain. Our aim is to critically discuss the role of RS in peculiar circumstances. In particular, we focus on the complex integration of genomic data with clinicopathological factors; the potential clinical impact of RS in node-positive premenopausal women and in the neoadjuvant setting; the significance of RS in special histologies and in male patients; and the management and time-optimisation of test ordering. In the absence of robust evidence in these areas, we provide perspectives for improving the use of the 21-gene assay in the decision-making process and guide adjuvant treatment decisions even in challenging cases.

Effect of polycyclic aromatic hydrocarbons on immunity

Nearly a quarter of the total number of deaths in the world are caused by unhealthy living or working environments. Therefore, we consider it significant to introduce the effect of a widely distributed component of air/water/food-source contaminants, polycyclic aromatic hydrocarbons (PAHs), on the human body, especially on immunity in this review. PAHs are a large class of organic compounds containing two or more benzene rings. PAH exposure could occur in most people through breath, smoke, food, and direct skin contact, resulting in both cellular immunosuppression and humoral immunosuppression. PAHs usually lead to the exacerbation of autoimmune diseases by regulating the balance of T helper cell 17 and regulatory T cells, and promoting type 2 immunity. However, the receptor of PAHs, aryl hydrocarbon receptor (AhR), appears to exhibit duality in the immune response, which seems to explain some seemingly opposite experimental results. In addition, PAH exposure was also able to exacerbate allergic reactions and regulate monocytes to a certain extent. The specific regulation mechanisms of immune system include the assistance of AhR, the activation of the CYP-ROS axis, the recruitment of intracellular calcium, and some epigenetic mechanisms. This review aims to summarize our current understanding on the impact of PAHs in the immune system and some related diseases such as cancer, autoimmune diseases (rheumatoid arthritis, type 1 diabetes, multiple sclerosis, and systemic lupus erythematosus), and allergic diseases (asthma and atopic dermatitis). Finally, we also propose future research directions for the prevention or treatment on environmental induced diseases.

Analysis of the Clinical Advancements for BRCA-Related Malignancies Highlights the Lack of Treatment Evidence for BRCA-Positive Male Breast Cancer

Male breast cancer (MBC) is a rare disease that accounts for less than 1% of all breast cancers and male malignancies. Despite recognised clinico-pathological and molecular differences to female breast cancer (FBC), the clinical management of MBC follows established FBC treatment strategies. Loss of function mutations in the DNA damage response genes BRCA1 and BRCA2, have been strongly implicated in the pathogenesis of MBC. While there have been extensive clinical advancements in other BRCA-related malignancies, including FBC, improvements in MBC remain stagnant. Here we present a review that highlights the lack of treatment evidence for BRCA-related MBC and the required national and global collaborative effort to address this unmet need. In doing so, we summarise the transformative clinical advancements with poly(ADP-ribose) polymerase (PARP) inhibitors in other BRCA-related cancers namely, FBC and prostate cancer.

High-throughput Proteomic Profiling of Male Breast Cancer Tissue

BACKGROUND/AIM

Until now, little emphasis has been placed on the protein expression profile of male breast cancer (MBC) tumors, due to the rarity of the disease. The present study aimed to identify a proteomic pattern that is characteristic for malignant male breast tissue epithelium.

MATERIALS AND METHODS

The protein content of four male breast tumors and corresponding adjacent healthy (control) tissues was analyzed by high-throughput nano-liquid chromatography-MS/MS technology.

RESULTS

A total of 2,352 proteins were identified, that correspond to 1,249 single gene products, with diverse biological roles. Of those, a panel of 119 differentially expressed tissue proteins was identified in MBC samples compared to controls; 90 were found to be over-expressed in MBC tissues, while 29 were down-regulated. Concurrently, 844 proteins were detected only in MBC tumors and 197 were expressed exclusively in control mammary samples.

CONCLUSION

Differential proteomic expression was found in MBC tissue, leading to improved understanding of MBC pathology and highlighting the need for personalized management of male patients.

Genomic analysis of focal nodular hyperplasia with associated hepatocellular carcinoma unveils its malignant potential: a case report

Background

Focal nodular hyperplasia (FNH) is typically considered a benign tumor of the liver without malignant potential. The co-occurrence of FNH and hepatocellular carcinoma (HCC) has been reported in rare cases. In this study we sought to investigate the clonal relationship between these lesions in a patient with FNH-HCC co-occurrence.

Methods

A 74-year-old female patient underwent liver tumor resection. The resected nodule was subjected to histologic analyses using hematoxylin and eosin stain and immunohistochemistry. DNA extracted from microdissected FNH and HCC regions was subjected to whole exome sequencing. Clonality analysis were performed using PyClone.

Results

Histologic analysis reveals that the nodule consists of an FNH and two adjoining HCC components with distinct histopathological features. Immunophenotypic characterization and genomic analyses suggest that the FNH is clonally related to the HCC components, and is composed of multiple clones at diagnosis, that are likely to have progressed to HCC through clonal selection and/or the acquisition of additional genetic events.

Conclusion

To the best of our knowledge, our work is the first study showing a clonal relationship between FNH and HCC. We show that FNH may possess the capability to undergo malignant transformation and to progress to HCC in very rare cases.

Mutational signatures in GATA3 transcription factor and its DNA binding domain that stimulate breast cancer and HDR syndrome

Transcription factors (TFs) play important roles in many biochemical processes. Many human genetic disorders have been associated with mutations in the genes encoding these transcription factors, and so those mutations became targets for medications and drug design. In parallel, since many transcription factors act either as tumor suppressors or oncogenes, their mutations are mostly associated with cancer. In this perspective, we studied the GATA3 transcription factor when bound to DNA in a crystal structure and assessed the effect of different mutations encountered in patients with different diseases and phenotypes. We generated all missense mutants of GATA3 protein and DNA within the adjacent and the opposite GATA3:DNA complex models. We mutated every amino acid and studied the new binding of the complex after each mutation. Similarly, we did for every DNA base. We applied Poisson-Boltzmann electrostatic calculations feeding into free energy calculations. After analyzing our data, we identified amino acids and DNA bases keys for binding. Furthermore, we validated those findings against experimental genetic data. Our results are the first to propose in silico modeling for GATA:DNA bound complexes that could be used to score effects of missense mutations in other classes of transcription factors involved in common and genetic diseases.

Clinicopathological features and prognosis of male breast cancer

Objective

We aimed to describe the differences in clinicopathological characteristics and overall survival (OS) between male and female breast cancer patients, and to develop a prognostic nomogram to predict survival in patients with male breast cancer (MBC).

Methods

Using the Surveillance, Epidemiology, and End Results database, we compared age, race, histological type, histological grade, tumor size, lymph node status, metastases, estrogen/progesterone receptor (ER/PR) and HER-2 status between male and female patients, and analyzed their relationships with OS. We established a nomogram and produced a calibration curve to observe its predictive effect.

Results

Age, race, T stage, N stage, bone and lung metastases, and histological type and grade differed between male and female patients. OS in male patients was related to age, tumor size, metastatic site, ER/PR status, and histological grade, but not to race or lymph node status. A nomogram was established, which showed good predictive performance for survival in MBC patients (area under the curve = 0.7).

Conclusion

MBC has a worse prognosis than female breast cancer, mainly characterized by late onset age, late staging, high proportion of invasive non-specific histological types, high histological grade, and luminal breast cancer.

Atlas of Lobular Breast Cancer Models: Challenges and Strategic Directions

Invasive lobular carcinoma (ILC) accounts for up to 15% of all breast cancer (BC) cases and responds well to endocrine treatment when estrogen receptor α-positive (ER+) yet differs in many biological aspects from other ER+ BC subtypes. Up to 30% of patients with ILC will develop late-onset metastatic disease up to ten years after initial tumor diagnosis and may experience failure of systemic therapy. Unfortunately, preclinical models to study ILC progression and predict the efficacy of novel therapeutics are scarce. Here, we review the current advances in ILC modeling, including cell lines and organotypic models, genetically engineered mouse models, and patient-derived xenografts. We also underscore four critical challenges that can be addressed using ILC models: drug resistance, lobular tumor microenvironment, tumor dormancy, and metastasis. Finally, we highlight the advantages of shared experimental ILC resources and provide essential considerations from the perspective of the European Lobular Breast Cancer Consortium (ELBCC), which is devoted to better understanding and translating the molecular cues that underpin ILC to clinical diagnosis and intervention. This review will guide investigators who are considering the implementation of ILC models in their research programs.

A biomarker study in Peruvian males with breast cancer

BACKGROUND

Breast cancer (BC) frequency in males is extremely low and tumor features vary from its female counterpart. Breast cancer clinical and pathological features differ by race in women. Tumor infiltrating lymphocyte (TIL) levels, mismatch repair (MMR) protein loss, androgen receptor (AR) expression, and PIK3CA gene mutations are predictive biomarkers of response to biological therapy in female BC. There is limited information about clinical and pathological features as well as predictive biomarkers in males of non-Caucasian races with BC.

AIM

To investigate clinicopathological features and biomarkers of BC tumors in males and their prognostic value in Peruvian population.

METHODS

This study looked at a single-institution series of 54 Peruvian males with invasive BC who were diagnosed from Jan 2004 to June 2018. Standard pathological features, TIL levels, MMR proteins, AR immunohistochemistry staining, and PIK3CA gene mutations were prospectively evaluated in cases with available paraffin material. Percentage of AR and estrogen receptor (ER) positive cells was additionally calculated by software after slide scanning. Statistical analyses included association tests, intraclass correlation test and Kaplan Meier overall survival curves.

RESULTS

The median age was 63 years and most cases were ER-positive (85.7%), HER2 negative (87.2%), Luminal-A phenotype (60%) and clinical stage II (41.5%) among our male breast tumors. Median TIL was 10% and higher levels tended to be associated with Luminal-B phenotype and higher grade. AR-positive was found in 85.3% and was correlated with ER (intraclass index of 0.835, P < 0.001). Loss of MMR proteins was found in 15.4% and PIK3CA mutation (H1047R) in 14.3% (belonged to the Luminal-A phenotype). Loss of MMR proteins was associated with AR-negative (P = 0.018) but not with ER (P = 0.43) or TIL (P = 0.84). Early stages (P < 0.001) and lower grade (P = 0.006) were associated with longer overall survival. ER status, phenotype, AR status, TIL level, MMR protein loss nor PIK3CA mutation was not associated with survival (P > 0.05).

CONCLUSION

Male BC is usually ER and AR positive, and Luminal-A. MMR loss and PIK3CA mutations are infrequent. Stage and grade predicted overall survival in our South American country population.

The Genomic Landscape of Serrated Lesion of the Colorectum: Similarities and Differences With Tubular and Tubulovillous Adenomas

Serrated lesions of the colorectum are the precursors of 15-30% of colorectal cancers (CRCs). These lesions have a peculiar morphological appearance, and they are more difficult to detect than conventional adenomatous polyps. In this study, we sought to define the genomic landscape of these lesions using high-depth targeted sequencing. Eight sessile serrated lesions without dysplasia (SSL), three sessile serrated lesions with dysplasia (SSL/D), two traditional serrated adenomas (TSA), and three tubular adenomas (TA) were retrieved from the files of the Institute of Pathology of the University Hospital Basel and from the GILAB AG, Allschwil, Switzerland. Samples were microdissected together with the matched normal counterpart, and DNA was extracted for library preparation. Library preparation was performed using the Oncomine Comprehensive Assay targeting 161 common cancer driver genes. Somatic genetic alterations were defined using state-of-the-art bioinformatic analysis. Most SSLs, as well as all SSL/Ds and TSAs, showed the classical BRAF p.V600E mutation. The BRAF-mutant TSAs showed additional alterations in CTNNB1, NF1, TP53, NRAS, PIK3CA, while TA showed a consistently different profile, with mutations in ARID1A (two cases), SMAD4, CDK12, ERBB3, and KRAS. In conclusion, our results provide evidence that SSL/D and TSA are similar in somatic mutations with the BRAF hotspot somatic mutation as a major driver of the disease. On the other hand, TAs show a different constellation of somatic mutations such as ARID1A loss of function.

A practical guide to endocrine therapy in the management of estrogen receptor-positive male breast cancer

The majority (more than 90%) of male breast cancers (MaBCs) are estrogen receptor-positive, such that endocrine therapy is the mainstay of MaBC treatment. Endocrine therapy has been associated with improved overall survival in observational studies on MaBC, though large randomized clinical trials have never been completed to confirm this benefit in this population. Tamoxifen is currently the preferred drug for both metastatic and adjuvant treatment of MaBC. Known differences in treatment patterns and hormonal milieu between men and women may warrant a unique approach to the management of toxicities in men. This review provides a detailed discussion of endocrine therapy for MaBC.

Male breast cancer: an update

Male breast cancer (MBC) is rare, accounting for less than 1% of all breast cancer but the incidence has increased worldwide. Risk factors include increased longevity, obesity, testicular diseases and tumours, and germline mutations of BRCA2. BRCA2 carriers have 80 times the risk of the general population. Men generally present with breast cancer at an older age compared with women. Histologically, MBC is often of grade 2, hormone receptor positive, HER2 negative, and no special type carcinoma although in situ and invasive papillary carcinomas are common. Reporting and staging are similar to female breast cancer. Metastatic lesions to the male breast do occur and should be differentiated from primary carcinomas. Until recently, MBC was thought to be similar to the usual ER positive post-menopausal female counterpart. However, advances in MBC research and trials have highlighted significant differences between the two. This review provides an up to date overview of the biology, genetics, and histology of MBC with comparison to female breast cancers and differential diagnosis from histological mimics.

Cystic Encapsulated Papillary Carcinoma in the Male Breast: An Unusual Feature With a Diagnostic Challenge

Papillary carcinoma in the male breast is uncommon. Here, we report a case of a large encapsulated papillary carcinoma (EPC) in a 62-year-old male. The patient presented with a left breast mass of 1-year duration and bloody nipple discharge for several days. Mammography and breast ultrasonography showed a large left breast mass. The initial biopsy demonstrated fat necrosis with acute and chronic inflammation only. Due to clinical suspicion, a repeat biopsy was performed and revealed scant fragments of papillary carcinoma in a background of inflammation. The patient underwent left total mastectomy. Grossly, the breast contained a 9.0 cm entirely cystic lesion lined by a hemorrhagic thick fibrotic wall. No solid area was identified in the cyst. The entire cyst wall was examined under microscopy; only a few sections with papillary carcinoma were identified. The lesion was confined to the cyst wall; so, a diagnosis of EPC was made. Compared to the previously reported EPC cases of male breast, the lesion of this case was unusually cystic, which making the diagnosis challenging. Therefore, awareness of this unusual feature, repeat biopsy when the pathology result is discordant, and extensive sampling of the lesion are essential for making the correct diagnosis and guiding patient management.

Differences in ultrasonographic features between males and females with breast cancer of the luminal A and luminal B molecular subtypes

AIM

To analyze the relationships between the ultrasonographic features and the molecular subtypes of breast cancer in men and women.

METHODS

Data were collected from 43 males and 80 females with breast cancer who were treated at our hospital. The following ultrasonographic characteristics of the tumors were evaluated: shape, orientation, margin, echo pattern, posterior features, calcifications, Color Doppler Flow Imaging, and Breast Imaging Reporting and Data System (BI-RADS) category.

RESULTS

On ultrasound, a nonparallel orientation, noncircumscribed margin, and attenuating posterior features were associated with luminal A lesions. A parallel orientation (P = 0.002), circumscribed margin (P = 0.04), no change in posterior features (P < 0.001), and the BI-RADS 4 category (P = 0.001) were significantly associated with luminal B lesions. In the group with luminal A lesions, male patients were older (P = 0.001) and a greater number of the tumors exhibited a regular shape (P = 0.009), circumscribed margin (P < 0.001), no change in posterior features (P < 0.001), and the BI-RADS 4 category (P < 0.001) than those in female patients. Male patients were older (P < 0.001) and a greater number showed a no change in posterior features (P < 0.001), spotty blood flow (P = 0.002), and the BI-RADS 4 category (P < 0.001) than female patients with masses of the luminal B subtype.

CONCLUSION

Obvious differences in the ultrasonographic and pathological features were noted between breast cancer in males and females, which provided the theoretical basis for the individualized treatment of breast cancer, particularly breast cancer in males.

Cardiovascular and Other Competing Causes of Death in Male Breast Cancer Patients: A Population-Based Epidemiologic Study

Purpose

Male breast cancer (MBC) is a rare disease that tends to occur in elderly men. Little is known about the causes of death in MBC because of the small sample size of most studies. This study aimed to investigate the causes of death in MBC patients.

Patients and Methods

MBC patient data were obtained from the Surveillance, Epidemiology, and End Results database (1975-2016). Time trends of MBC mortality in the US population were analyzed using Joinpoint software. We calculated the proportion of each cause of death in the overall cohort and in different patient subgroups. Competing risk models were used to calculate cumulative mortality at different follow-up times. The risk of cardiovascular death (CVD) in MBC patients was compared to that of the age-matched general population by calculating standardized mortality ratio (SMR).

Results

In total, 6426 patients were included in the analysis. MBC mortality rate increased between 2004 and 2019 (annual percentage change=1.16, 95% confidence interval [CI]: 0.50, 1.80). There were 1757 patients (27.3%) who died of non-breast cancer causes. CVD was the leading cause of death in patients who were elderly or had localized disease. MBC patients had a 6.58-fold higher risk of CVD than the general population (SMR=6.58, 95% CI: 6.14, 7.05).

Conclusion

Non-breast cancer death accounts for the majority of deaths in MBC patients who are elderly or have localized cancer. Compared to the general population, MBC patients have an increased risk of CVD. These results highlight the importance of monitoring cardiovascular comorbidities in MBC patients.

A Systematic Comparison of Overall Survival Between Men and Women With Triple Negative Breast Cancer

INTRODUCTION

Triple-negative breast cancer (TNBC) in men is very rare. The clinical characteristics, prognostic factors, and overall survival of men with TNBC have not been characterized.

METHODS

The study population consisted of men and women with a diagnosis of stage I-III TNBC between 2010 and 2016 in the National Cancer Database. Baseline demographic and tumor characteristics between men and women were compared using Pearson's Chi-Square test for categorical variables and Mann-Whitney U test for continuous variables. Kaplan-Meier and multivariate Cox proportional hazards regression model was used to compare survival and identify prognostic factors.

RESULTS

A total of 311 men and 95,406 women with TNBC were included in the final analysis. The 3-year and 5-year overall survival was 74.8% and 68.8% in men, while it was 83.2% and 74.8% in women, respectively. In multivariate analysis, men were found to have a significantly worse overall survival compared to women (HR, 1.49, 95% CI, 1.19-1.86, P= .01). Older age at diagnosis, higher TNM stage, undergoing mastectomy and not undergoing chemotherapy or radiation were identified as independent negative prognostic factors in men with TNBC.

CONCLUSION

In one of the largest studies of men with TNBC, men were noted to have a poorer overall survival compared to women, despite adjusting for usual prognostic factors. Further research into differences in tumor biology, treatment patterns and compliance with therapy between men and women are needed to understand the underlying etiologies for the survival difference in TNBC.

Genetic Landscape of Male Breast Cancer

Male breast cancer (MBC) is now considered molecularly different from female breast cancer (FBC). Evidence from studies indicates that common genetic and epigenetic features of FBC are not shared with those diagnosed in men. Genetic predisposition is likely to play a significant role in the tumorigenesis of this rare disease. Inherited germline variants in BRCA1 and BRCA2 account for around 2% and 10% of MBC cases, respectively, and the lifetime risk of breast cancer for men harboring BRCA1 and BRCA2 mutations is 1.2% and 6.8%. As for FBC, pathogenic mutations in other breast cancer genes have also been recently associated with an increased risk of MBC, such as PALB2 and CHEK2 mutations. However, while multigene germline panels have been extensively performed for BC female patients, the rarity of MBC has resulted in limited data to allow the understanding of the magnitude of risk and the contribution of recently identified moderate penetrance genes of FBC for MBC predisposition. This review gathers available data about the germline genetic landscape of men affected by breast cancer, estimated risk associated with these genetic variants, and current guidelines for clinical management.

Paired Tumor-Normal Sequencing Provides Insights Into the TP53-Related Cancer Spectrum in Patients With Li-Fraumeni Syndrome

BACKGROUND

Genetic testing for Li-Fraumeni syndrome (LFS) is performed by using blood specimens from patients selected based on phenotype-dependent guidelines. This approach is problematic for understanding the LFS clinical spectrum because patients with nonclassical presentations are missed, clonal hematopoiesis-related somatic blood alterations cannot be distinguished from germline variants, and unrelated tumors cannot be differentiated from those driven by germline TP53 defects.

METHODS

To provide insights into the LFS-related cancer spectrum, we analyzed paired tumor-blood DNA sequencing results in 17 922 patients with cancer and distinguished clonal hematopoiesis-related, mosaic, and germline TP53 variants. Loss of heterozygosity and TP53 mutational status were assessed in tumors, followed by immunohistochemistry for p53 expression on a subset to identify those lacking biallelic TP53 inactivation.

RESULTS

Pathogenic/likely pathogenic TP53 variants were identified in 50 patients, 12 (24.0%) of which were clonal hematopoiesis related and 4 (8.0%) of which were mosaic. Twelve (35.3%) of 34 patients with germline TP53 variants did not meet LFS testing criteria. Loss of heterozygosity of germline TP53 variant was observed in 96.0% (95% confidence interval [CI] = 79.7% to 99.9%) of core LFS spectrum-type tumors vs 45.5% (95% CI = 16.8% to 76.6%) of other tumors and 91.3% (95% CI = 72.0% to 98.9%) of tumors from patients who met LFS testing criteria vs 61.5% (95% CI = 31.6% to 86.1%) of tumors from patients who did not. Tumors retaining the wild-type TP53 allele exhibited wild-type p53 expression.

CONCLUSIONS

Our results indicate that some TP53 variants identified in blood-only sequencing are not germline and a substantial proportion of patients with LFS are missed based on current testing guidelines. Additionally, a subset of tumors from patients with LFS do not have biallelic TP53 inactivation and may represent cancers unrelated to their germline TP53 defect.

Comparison between male and female breast cancer survival using propensity score matching analysis

Male breast cancer (MBC) is a rare disease. The few studies on MBC reported conflicting data regarding survival outcomes compared to women. This study has two objectives: to describe the characteristics of a single-cohort of MBC and to compare overall survival (OS) and disease-free survival (DFS) between men and women using the propensity score matching (PSM) analysis. We considered MBC patients (n = 40) diagnosed between January 2004 and May 2019. Clinical, pathological, oncological and follow-up data were analyzed. Univariate analysis was performed to determine the prognostic factors on OS and DFS for MBC. We selected female patients with BC (n = 2678). To minimize the effect of the imbalance of the prognostic factors between the two cohorts, the PSM method (1:3 ratio) was applied and differences in survival between the two groups were assessed. The average age of MBC patients was 73 years. The 5-year OS and DFS rates were 76.7% and 72.2% respectively. The prognostic factors that significantly influenced OS and DFS were tumor size and lymph node status. After the PSM, 5 year-OS was similar between MBC and FBC (72.9% vs 72.3%, p = 0.70) while we found a worse DFS for MBC (72.2% vs 91.4%, p  = 0.03). Our data confirmed previous reported MBC characteristics: we found a higher risk of recurrence in MBC compared to FMC but similar OS. MBC and FMC are different entities and studies are needed to understand its epidemiology and guide its management.

Non-viral gene delivery of the oncotoxic protein NS1 for treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is related to increasing incidence rates and poor clinical outcomes due to lack of efficient treatment options and emerging resistance mechanisms. The aim of the present study is to exploit a non-viral gene therapy enabling the expression of the parvovirus-derived oncotoxic protein NS1 in HCC. This anticancer protein interacts with different cellular kinases mediating a multimodal host-cell death. Lipoplexes (LPX) designed to deliver a DNA expression plasmid encoding NS1 are characterized using a comprehensive set of in vitro assays. The mechanisms of cell death induction are assessed and phosphoinositide-dependent kinase 1 (PDK1) is identified as a potential predictive biomarker for a NS1-LPX-based gene therapy. In an HCC xenograft mouse model, NS1-LPX therapeutic approach results in a significant reduction in tumor growth and extended survival. Data provide convincing evidence for future studies using a targeted NS1 gene therapy for PDK1 overexpressing HCC.

The beneficial role of Asian-based RecurIndex test in the prognostic prediction in Chinese male breast cancer patients

RecurIndex, a multigene profiling assay, can predict the risk of local recurrence and distant metastasis in female breast cancer (FBC), but its role in male breast cancer (MBC) remains unclear. In this study, the clinicopathological data of 43 consecutive MBC patients undergoing surgeries between 2009 and 2018 were retrospectively analysed. Their paraffin-embedded tissue sections were examined by RecurIndex test which comprised 2 models: recurrence index for local recurrence (RI-LR) and recurrence index for distant recurrence (RI-DR). Of 43 patients, there were 26 low-risk and 17 high-risk patients assessed by RI-LR, while 17 low-risk and 26 high-risk patients by RI-DR. For RI-LR, tumor N stage showed statistically significant (P < 0.001) between low- and high-risk patients; for RI-DR, differences were pronounced in tumor grade (P = 0.033), T stage (P = 0.043) and N stage (P = 0.003). In terms of clinical outcomes, the overall survival (OS) of low- and high-risk patients stratified by RI-LR showed no statistically significant differences (P = 0.460), while high-risk patients identified by RI-DR had a significantly worse distant recurrence-free survival (DRFS) (P = 0.035), progression-free survival (PFS) (P = 0.019) and OS (P = 0.044) than low-risk patients. Overall, RI-DR can effectively predict the DRFS, PFS and OS of MBC patients and identify those at low risk of recurrence, which may serve as a potential prognostic tool for MBC.

Management and outcome of male metastatic breast cancer in the national multicenter observational research program Epidemiological Strategy and Medical Economics (ESME)

Background and Aims:

Because of its low prevalence, metastatic breast cancer (MBC) in males is managed based on clinical experience with women. Using a real-life database, we aim to provide a comprehensive analysis of male MBC characteristics, management and outcome.

Methods:

The Epidemiological Strategy and Medical Economics Data Platform collected data for all men and women ⩾18 years with MBC in 18 participating French Comprehensive Cancer Centers from January 2008 to November 2016. Demographic, clinical, and pathological characteristics were retrieved, as was treatment modality. Men were matched 1:1 to women with similar characteristics.

Results:

Of 16,701 evaluable patients, 149 (0.89%) men were identified. These men were older (median age 69 years) and predominantly had hormone receptor HR+/HER2– disease (78.3%). Median overall survival (OS) was 41.8 months [95% confidence interval (CI: 26.9–49.7)] and similar to women. Median progression-free survival (PFS) with first-line therapy was 9.3 months [95% CI (7.4–11.5)]. In the HR+/HER2– subpopulation, endocrine therapy (ET) alone was the frontline treatment for 43% of patients, including antiestrogens (n = 19), aromatase inhibitors (n = 15) with luteinizing hormone-releasing hormone (LHRH) analogs (n = 3), and various sequential treatments. Median PFS achieved by frontline ET alone was similar in men [9.8 months, 95% CI (6.9–17.4)] and in women [13 months, 95% CI (8.4–30.9)] (p = 0.80). PFS was similar for HR+/HER2– men receiving upfront ET or chemotherapy: 9.8 months [95% CI (6.9–17.4)] versus 9.5 months [95% CI (7.4–11.7)] (p = 0.22), respectively.

Conclusion:

MBC management in men and women leads to similar outcomes, especially in HR+/HER2– patients for whom ET should also be a cornerstone. Unsolved questions remain and successfully recruiting trials for men are still lacking.

Prolonged benefit from palbociclib plus letrozole in heavily pretreated advanced male breast cancer: case report

INTRODUCTION

Breast cancer in men is less common than in women and treatment recommendations are often derived from clinical trials exclusively involving women. Data on efficacy of CDK 4/6 inhibitors, which are the mainstay of treatment for hormone receptor-positive/HER2-negative advanced breast cancer, are lacking in male patients.

CASE REPORT

We present a clinical case of prolonged benefit from palbociclib in combination with letrozole and LHRH analogue in a man who had previously been treated with six lines of endocrine therapies and chemotherapy regimens but was still in excellent clinical condition.

CONCLUSIONS

This clinical case demonstrates that male breast cancer stands out as an endocrine-sensitive disease, which could potentially benefit from CDK 4/6 inhibitors in combination with endocrine agents even in very heavily pretreated settings of disease, underscoring both the importance of an accurate selection of patients for later treatment lines, taking into account disease history and previous treatment responses, and the peculiarity of breast cancer in men, which deserves dedicated clinical trials to tailor future recommendations.

Deciphering the clonal relationship between glandular and squamous components in adenosquamous carcinoma of the lung using whole exome sequencing

Adenosquamous carcinoma of the lung (ASC) is a rare subtype of non-small cell lung cancer, consisting of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) components. ASC shows morphological characteristics of classic LUAD and LUSC but behaves more aggressively. Although ASC can serve as a model of lung cancer heterogeneity and transdifferentiation, its genomic background remains poorly understood. In this study, we sought to explore the genomic landscape of macrodissected LUAD and LUSC components of three ASC using whole exome sequencing (WES). Identified truncal mutations included the pan-cancer tumor-suppressor gene TP53 but also EGFR, BRAF, and MET, which are characteristic for LUAD but uncommon in LUSC. No truncal mutation of classical LUSC driver mutations were found. Both components showed unique driver mutations that did not overlap between the three ASC. Mutational signatures of truncal mutations differed from those of the branch mutations in their descendants LUAD and LUSC. Most common signatures were related to aging (1, 5) and smoking (4). Truncal chromosomal copy number aberrations shared by all three ASC included losses of 3p, 15q and 19p, and an amplified region in 5p. Furthermore, we detected loss of STK11 and SOX2 amplification in ASC, which has previously been shown to drive transdifferentiation from LUAD to LUSC in preclinical mouse models. Conclusively, this is the first study using WES to elucidate the clonal evolution of ASC. It provides strong evidence that the LUAD and LUSC components of ASC share a common origin and that the LUAD component appears to transform to LUSC.

MPA/DMBA-driven mammary carcinomas

The polycyclic aromatic hydrocarbon 7,12-dimethylbenz[a]anthracene (DMBA, D) administered per os to wild-type female mice bearing slow-release medroxyprogesterone (MPA, M) pellets s.c. drives the formation of mammary carcinomas that recapitulate numerous immunobiological features of human luminal B breast cancer. In particular, M/D-driven mammary carcinomas established in immunocompetent C57BL/6 female mice (1) express hormone receptors, (2) emerge by evading natural immunosurveillance and hence display a scarce immune infiltrate largely polarized toward immunosuppression, (3) exhibit exquisite sensitivity to CDK4/CDK6 inhibitors, and (4) are largely resistant to immunotherapy with immune checkpoint blockers targeting PD-1. Thus, M/D-driven mammary carcinomas evolving in immunocompetent female mice stand out as a privileged preclinical platform for the study of luminal B breast cancer. Here, we provide a detailed protocol for the establishment of M/D-driven mammary carcinomas in wild-type C57BL/6 female mice. This protocol can be easily adapted to generate M/D-driven mammary carcinomas in female mice with most genetic backgrounds (including genetically-engineered mice).

Subtyping of male breast cancer by PAM50 and immunohistochemistry: a pilot study of a consecutive Danish cohort

Male breast cancer (MBC) is a rare disease that is still to be fully understood. In female breast cancer, molecular subtyping by gene expression has proven its significance. In this study, we characterize a consecutive cohort of MBC patients surgically treated from 1997 to 2017, identified at our institution (N = 37), and report the association between molecular subtypes found by a surrogate panel of immunohistochemical (IHC) markers, and the PAM50 signature, as well as risk of recurrence score and overall survival for the different subtypes. PAM50 subtypes were determined using the nCounter FLEX system instrument and software. The distribution of molecular subtypes according to the PAM50 signature was as follows: 56% luminal B, 39% luminal A, and 5% basal-like. None of the tumors were HER2-enriched. Using IHC surrogate markers, we found 80% luminal B-like, 15% luminal A-like, and 5% basal-like. None were HER2-positive (non-luminal). We found a strong statistical association between subtypes found by PAM50 signature and the IHC surrogate markers (p < 0.001). Furthermore, we found luminal A tumors to be smaller in size compared to luminal B tumors (p = 0.04). Patients with luminal A subtype tumors had the lowest ROR scores with a mean of 39, whereas patients with luminal B subtype tumors had a mean ROR score of 69. Significant worse overall survival for luminal B tumors compared to luminal A tumors was seen (p = 0.02). Male breast cancer seems to be a mainly luminal disease, with luminal B being the most frequent subtype. Further studies are needed to ensure correct therapeutic strategies for this select group of patients.

Adjuvant treatment of early male breast cancer

PURPOSE OF REVIEW

Male breast cancer (MaBC) is a rare disease, and some challenges exist in its management because current treatment recommendations are extrapolated from trials that mostly excluded men. This review will revise all available data that could improve the treatment of MaBC, with a special focus on adjuvant systemic treatments.

RECENT FINDINGS

To date, men with hormone receptor-positive breast cancer, who are candidates for adjuvant endocrine therapy, should be offered tamoxifen (TAM) for five years. Additional five years are possible, according to tolerance and recurrence risk. If TAM is contraindicated, a gonadotropin-releasing hormone (GnRH) agonist or antagonist and aromatase inhibitor should be proposed. Chemotherapy and targeted therapy in the other breast cancer subtypes should be used with the same indications offered to women with breast cancer. All men with breast cancer should be offered genetic counseling and germline genetic testing of cancer predisposition genes.

SUMMARY

For decades, men with breast cancer have been treated suboptimally and denied the participation in clinical trials. Recently, many clinical trials started enrolling both genders, as strongly endorsed by the Food and Drug Administration. Hopefully, this turnaround will help subdue the disparities in the quality of care.

Characteristics of male triple negative breast cancer: A population-based study

Male triple negative breast cancer (TNBC), which lacks expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), is a very rare entity, comprising only a very small percentage of all male breast cancer cases. Management strategies are typically based off research conducted in female TNBC patients; however, there is still much that remains unknown in the male cohort, such as risk factors for developing these malignancies, the optimal treatment approach, and both short-term and long-term outcome data. In this retrospective cohort study, we aimed to address these concerns by assessing both the characteristics of male patients who develop TNBC as well as their outcomes. We harnessed data from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program and identified 66 male patients diagnosed with TNBC between 2010 and 2016. Patients were stratified by several variables including age, insurance status, time period of diagnosis, histology, nodal status, tumor grade, tumor stage at diagnosis, and treatment strategy employed for the assessment of overall survival (OS) differences. Our analysis demonstrated that stage remains the most important prognostic factor for OS, with higher stage corresponding to worse OS. A significant OS benefit was also identified in men undergoing a total mastectomy, compared to partial mastectomy or no surgery at all. We also identified that male patients are more likely to present with more advanced disease stages compared to their female counterparts and, therefore, have worse outcomes on average. This may be due to various factors, including the rarity of male TNBC cases and less clear screening guidelines for male breast cancer in general. Trends toward poorer OS with higher tumor grade, higher tumor T stage, advanced age, earlier time period of diagnosis, and ductal histology were also identified, but did not achieve statistical significance. The remaining variables did not appear to influence outcomes in a meaningful manner. In summary, our study suggests, similar to population studies of women with TNBC, that tumor stage is a major prognostic factor of OS in men with TNBC. The data also suggest that the surgical treatment strategy employed is also likely of significance, with improved OS being seen with total mastectomies over partial mastectomies. Other variables such as tumor grade and T stage also likely play a role, but did not achieve statistical significance owing to the small population size. Owing to the rarity of cases, further studies of male TNBC are needed to better understand this rare entity and guide future management strategies.

Prevention of dsRNA-induced interferon signaling by AGO1x is linked to breast cancer cell proliferation

Translational readthrough, i.e., elongation of polypeptide chains beyond the stop codon, was initially reported for viral RNA, but later found also on eukaryotic transcripts, resulting in proteome diversification and protein‐level modulation. Here, we report that AGO1x, an evolutionarily conserved translational readthrough isoform of Argonaute 1, is generated in highly proliferative breast cancer cells, where it curbs accumulation of double‐stranded RNAs (dsRNAs) and consequent induction of interferon responses and apoptosis. In contrast to other mammalian Argonaute protein family members with primarily cytoplasmic functions, AGO1x exhibits nuclear localization in the vicinity of nucleoli. We identify AGO1x interaction with the polyribonucleotide nucleotidyltransferase 1 (PNPT1) and show that the depletion of this protein further augments dsRNA accumulation. Our study thus uncovers a novel function of an Argonaute protein in buffering the endogenous dsRNA‐induced interferon responses, different than the canonical function of AGO proteins in the miRNA effector pathway. As AGO1x expression is tightly linked to breast cancer cell proliferation, our study thus suggests a new direction for limiting tumor growth.

MARCKS protein overexpression is associated with poor prognosis in male breast cancer

BACKGROUND

Male breast cancer (MBC) is a rare and aggressive disease. Thus, identification of new therapeutic targets is crucial.

OBJECTIVE

Our objective was to evaluate the protein expression of MARCKS (Myristoylated Alanine-Rich C-Kinase Substrate) in MBC and to investigate its prognostic value.

MATERIALS AND METHODS

MARCKS protein expression in tumor and stromal cells was analyzed by immunohistochemistry (IHC) in a retrospective series of 96 pre-chemotherapy MBC samples and 80 normal breast samples, from Tunisian patients treated at Salah Azaiez Institute. Correlations were searched between MARCKS expression and clinicopathological features including overall survival (OS).

RESULTS

MARCKS was overexpressed in epithelial tumor cells in 66% of the MBC samples versus 26% of normal samples (p= 1.40 × 10-7). Such positive MARCKS expression in epithelial tumor cells was associated with positive HER2 status (p= 4.0 × 10-3). It was associated with shorter OS in uni-and multivariate analysis. By contrast, stromal IHC MARCKS expression was correlated only with tumor grade.

CONCLUSION

MARCKS tumor cell overexpression might in part explain the aggressiveness and the poor prognosis of MBC. MARCKS can represent a potential therapeutic target for MBC.

Pharmacological management of male breast cancer

INTRODUCTION

Despite its rarity, male breast cancer shows a steadily rising incidence. Given the absence of ad hoc prospective randomized clinical trials, treatment strategies are based on extrapolation from female breast cancer recommendations or solely on population-based data.

AREAS COVERED

This review discusses the current treatment landscape for male breast cancer in the adjuvant and in the metastatic setting. The authors also discuss the biology and genomic landscape of male breast cancer. Original research and review articles, relative to the period 2010-2019, were included in the review of the literature.

EXPERT OPINION

There is a major medical need to include male patients with breast cancer in prospective clinical trials. The call to equality in breast cancer care can be pursued via two divergent paths: (i) a gender-neutral delivery of breast cancer information and (ii) the creation of separate sections, for the more common female breast cancer and for the rare male ones. We propose to differentiate male breast cancer care, acknowledging unique onco-sexual and social needs that can be only partially shared.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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