BRCA1/BRCA2 mutation status and clinical-pathologic features of 108 male breast cancer cases from Tuscany: a population-based study in central Italy

Molecular characteristics of Asian male BRCA-related cancers

PURPOSE

Germline mutations of BRCA1 or BRCA2 predispose men to develop various cancers, including breast cancers and prostate cancers. Male breast cancer (MBC) is a rare disease while prostate cancer (PRC) is uncommon in young men at the age of less than 40. The prevalence of BRCA genes in Asian male patients has to be elevated.

METHODS

Germline mutations screening was performed in 98 high-risk Chinese MBC and PRC patients.

RESULT

We have identified 16 pathogenic BRCA2 mutation carriers, 12 were MBC patients, 2 were PRC patients and 2 were patients with both MBC and PRC. The mutation percentages were 18.8%, 6.7% and 50% for MBC, PRC and both MBC and PRC patients, respectively. BRCA2 gene mutations confer a significantly higher risk of breast/prostate cancers in men than those with BRCA1 mutations. BRCA mutated MBC patients had a younger age of diagnosis and strong family histories of breast cancers while BRCA mutated PRC patients had strong family histories of ovarian cancers.

CONCLUSION

Male BRCA carriers with breast cancers or prostate cancers showed distinct clinical and molecular characteristics, a male-specific genetic screening model would be useful to identify male cancer patients who have a high risk of BRCA mutation.

Using species richness calculations to model the global profile of unsampled pathogenic variants: Examples from BRCA1 and BRCA2

There have been many surveys of genetic variation in BRCA1 and BRCA2 to identify variant prevalence and catalogue population specific variants, yet none have evaluated the magnitude of unobserved variation. We applied species richness estimation methods from ecology to estimate "variant richness" and determine how many germline pathogenic BRCA1/2 variants have yet to be identified and the frequency of these missing variants in different populations. We also estimated the prevalence of germline pathogenic BRCA1/2 variants and identified those expected to be most common. Data was obtained from a literature search including studies conducted globally that tested the entirety of BRCA1/2 for pathogenic variation. Across countries, 45% to 88% of variants were estimated to be missing, i.e., present in the population but not observed in study data. Estimated variant frequencies in each country showed a higher proportion of rare variants compared to recurrent variants. The median prevalence estimate of BRCA1/2 pathogenic variant carriers was 0.64%. BRCA1 c.68_69del is likely the most recurrent BRCA1/2 variant globally due to its estimated prevalence in India. Modeling variant richness using ecology methods may assist in evaluating clinical targeted assays by providing a picture of what is observed with estimates of what is still unknown.

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.

A systematic literature review of the management, oncological outcomes and psychosocial implications of male breast cancer

BACKGROUND

Although male breast cancer (MBC) is a rare disease, accounting for <1% of all breast cancers, it has significant oncological, survival and psychosocial implications for patients. The aim of this study is to assess the latest literature in the diagnosis, management, oncological outcomes, and psychosocial impact of MBC.

METHODS

A systematic literature review was conducted using the PRISMA guidelines (Moher et al., 2009) [1] to explore the management of MBC, with particular focus on investigative imaging, surgical management, oncological outcomes, survival, genetic screening and psychosocial effects. Electronic databases were searched for randomised control trials, cohort studies and case series involving more than 10 patients. Imaging and surgical techniques, local and distant disease recurrence, survival, genetic screening and psychosocial implications in the setting of MBC were assessed.

RESULTS

The search criteria identified 199 articles, of which 59 met the inclusion criteria. This included 39,529 patients, with a mean age of 64.5 years (55-71), and a mean follow-up of 66.3 months (26.2-115). Mastectomy remains the most frequently used surgical technique, with an average of 89.6%. Loco-regional and distant recurrence rate was 10.1% and 21.4% respectively. Disease-free survival (DFS) at 5 and 10 years was 66.8% and 54.5% respectively. Disease-specific survival (DSS) at 5 and 10 years was 87.1% and 67.1% respectively. Overall survival (OS) at 5 and 10 years was 72.7% and 50.7% respectively. Genetic screening was conducted in 38.6% of patients of which 4.8% and 15.8% were found to be BRCA1 and BRCA2 carriers respectively. Psychosocial studies were conducted mainly using questionnaire and interview-based methodology focusing primarily on awareness of breast cancer in men, support available and impact on gender identity.

CONCLUSIONS

This review demonstrates that men present with later stage disease with subsequent impact on survival outcomes. There remains a paucity of high-level evidence and prospective studies are required. There is a need for increasing awareness amongst the public and health care professionals in order to improve outcomes and reduce stigma associated with MBC.

Male Breast Cancer: An Updated Review of Epidemiology, Clinicopathology, and Treatment

Male breast cancer (MaBC) is a rare clinical entity, which makes up approximately 1% of all breast cancers. However, the incidence of MaBC has been steadily increasing over the past few decades. The risk factors for MaBC include age, black race, family history of breast cancer, genetic mutations, liver cirrhosis, and testicular abnormalities. The majority of patients with MaBC present with painless lumps, and about half of the patients have at least one lymph node involved at the time of diagnosis. The treatment of MaBC models that of female breast cancer (FeBC), but this is mainly due to lack of prospective studies for MaBC patients. The treatment modality includes surgery, adjuvant radiation, endocrine therapy, and chemotherapy. However, there are some distinct features of MaBC, both clinically and molecularly, that may warrant a different clinical approach. Ongoing multinational effort is required, to conduct clinical trials for MaBC, or the inclusion of MaBC patients in FeBC trials, to help clinicians improve care for MaBC patients.

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.

Genetic predisposition to male breast cancer in Poland

BACKGROUND

Breast cancer in men accounts for fewer than 1 % of all breast cancer cases diagnosed in men and women. Genes which predispose to male breast cancer include BRCA1 and BRCA2. The role of other genes is less clear. In Poland, 20 founder mutations in BRCA1, BRCA2, CHEK2, PALB2, NBN, RECQL are responsible for the majority of hereditary breast cancer cases in women, but the utility this genes panel has not been tested in men.

METHODS

We estimated the prevalence of 20 alleles in six genes (BRCA1, BRCA2, CHEK2, PALB2, NBN, RECQL) in 165 Polish male breast cancer patients. We compared the frequency of selected variants in male breast cancer cases and controls.

RESULTS

One of the 20 mutations was seen in 22 of 165 cases (13.3%). Only one BRCA1 mutation and two BRCA2 mutations were found. We observed statistically significant associations for PALB2 and CHEK2 truncating mutations. A PALB2 mutation was detected in four cases (OR = 11.66; p < 0.001). A CHEK2 truncating mutation was detected in five cases (OR = 2.93;p = 0.02).

CONCLUSION

In conclusion, we recommend that a molecular test for BRCA1, BRCA2, PALB2 and CHEK2 recurrent mutations should be offered to male breast cancer patients in Poland.

Presentation and Spectrum of Male Breast Cancer in a Rural Cancer Center in a Subunit of Tata Memorial Center, India

This is a retrospective study of the incidence and clinical profile of male breast cancer (MBC) presenting to a rural cancer center in Punjab, India. All MBC cases registered over a period of 4.5 years from January 2015 to July 2019 were included. The study included 34 MBC patients accounting for 1.9% of all breast cancer cases with median age of 62.5 years. All patients were from Punjab except one, with majority from district Sangrur. Family history was present in 7 (20.6%) patients. Mean BMI (n = 23) was 24.8. The median duration of symptoms was 6 months (range 1-60 months). Main complaint was lump in 58.8% of patients followed by lump with ulceration (41.2%). All cases were mostly unilateral, left in 21 (61.8%) and right in 13 (38.2%), and one had bilateral breast cancer. Most tumors were centrally located (70.6%). Infiltrating ductal carcinoma and grade 3 were the commonest histology. ER positivity was high seen in 76.5% cases. In our study, 16 (47.1%) patients presented with distant metastasis at the time of diagnosis, and 10 (39.1%) were locally advance. Bone (41%) followed by lung (17%) were the most common sites of metastasis. Thirteen patients were treated radically, nine were treated with palliative intent, and twelve patients defaulted. Median follow-up period was 16.5 months. MBC constituted 1.9% of all breast cancers registered at our institute, which is higher than worldwide average. Our study population had a longer time to presentation, and majority were metastatic.

BRCA and PALB2 mutations in a cohort of male breast cancer with one bilateral case

INTRODUCTION

Male Breast Cancer (MBC) is a rare disease, about 1% of all breast cancers worldwide and less than 1% of cancers occurring in men. The bilateral male breast cancer (bMBC) is extremely rare. Germline mutations of BRCA1/BRCA2 genes are associated with a significantly increased risk of cancer in MBC; the role of PALB2 remains to be clarified. Our main goal was to provide contribution on characterization of BRCA1/BRCA2 and PALB2 mutations in MBC patients.

METHODS

We observed 28 MBC cases; one of them was a bMBC. Screening for BRCA1, BRCA2 and PALB2 genes was performed on all 28 MBC patients. Mutational analysis was extended to family members of mutated patients.

RESULTS

In our study, the MBC incidence was 5.2% and for bMBC was 3.6%. Mutation analysis showed pathogenic mutations in 11/28 (39.3%) patients; 2/28 (7.1%) displayed a mutation in BRCA1, 8/28 (28.6%) in BRCA2 and 1/28 (3.6%) in PALB2. Out of 11 mutated patients, one (9.1%) reported a double mutation in BRCA2. Personal history of other cancers was reported in 2/28 (7.1%) patients affected by bladder cancer. A first/second degree family history of breast/ovarian and other cancers occurred in 23/28 (82.1%) patients.

CONCLUSION

Our findings indicate BRCA2 as the main MBC susceptibility gene and describe an increased risk of bMBC and bladder cancer in mutated patients. The identification of mutations in MBC susceptibility genes supports the usage of oncology prevention programs in affected patients and their relatives carrying the mutation.

Male breast cancer: a neglected disease

Male breast cancer (MBC) is rare, tending to afflict sedentary men, with adolescent obesity being a risk factor. Men fare worse compared with matched females with breast cancer. The preponderance of ER+ve disease affects the molecular profile: most cases have luminal A tumors. Through male ignorance and risk-taking, delay is frequent and this lacuna needs addressing with health education. The major gene mutation responsible for MBC is BRCA2. Five single nucleotide polymorphisms (SNPs) are significantly and uniquely associated with MBC risk with two located in the 8q24.21 regions. Mastectomy is being gradually replaced by nipple-preserving surgery and radiotherapy but this trend could be expedited with neoadjuvant endocrine therapy. Significant advances will occur only after expansion of collaborative groups and this is a matter of pressing importance.

Reviewing the characteristics of BRCA and PALB2-related cancers in the precision medicine era

Germline mutations in BRCA1 and BRCA2 (BRCA) genes confer high risk of developing cancer, especially breast and ovarian tumors. Since the cloning of these tumor suppressor genes over two decades ago, a significant amount of research has been done. Most recently, monoallelic loss-of-function mutations in PALB2 have also been shown to increase the risk of breast cancer. The identification of BRCA1, BRCA2 and PALB2 as proteins involved in DNA double-strand break repair by homologous recombination and of the impact of complete loss of BRCA1 or BRCA2 within tumors have allowed the development of novel therapeutic approaches for patients with germline or somatic mutations in said genes. Despite the advances, especially in the clinical use of PARP inhibitors, key gaps remain. Now, new roles for BRCA1 and BRCA2 are emerging and old concepts, such as the classical two-hit hypothesis for tumor suppression, have been questioned, at least for some BRCA functions. Here aspects regarding cancer predisposition, cellular functions, histological and genomic findings in BRCA and PALB2-related tumors will be presented, in addition to an up-to-date review of the evolution and challenges in the development and clinical use of PARP inhibitors.

5-alpha Reductase Inhibitors and risk of male breast cancer: a systematic review and meta-analysis

OBJECTIVE

To assess the relationship between 5α-reductase inhibitors (5ARIs) and the risk of male breast cancer (MBC).

MATERIAL AND METHODS

We systematically searched Medline via PubMed, Embase and the Cochrane Library Central Register up to May 2017 to identify published articles related to 5ARIs and the risk of MBC.

RESULTS

Summary effect estimates were calculated by a random-effect model, and tests for multivariable-unadjusted pooled risk ratios (RR) and heterogeneity, as well as the sensitivity analyses were conducted to assess publication bias. All four studies were conducted in a quality assessment according to the Newcastle Ottawa Scale system. The strength of association between 5ARIs and the prevalence of MBC was evaluated by using summarized unadjusted pooled RR with a 95% confidence interval [CI]. Four studies involving 595.776 participants, mean age range from 60 to 73.2 years old, were included in a meta-analysis, which produced a summary unadjusted RR of the risk of MBC for the treatment of 5ARIs of 1.16 (95% CI 0.85-1.58, P=0.36) and the multivariable-adjusted RR is 1.03, (95% CI 0.75-1.41, p=0.86). There was no heterogeneity among included studies (I2=0%, P=0.49). Estimates of total effects were generally consistent with the sensitivity.

CONCLUSION

We did not observe a positive association between the use of 5ARIs and MBC. The small number of breast cancer cases exposed to 5ARIs and the lack of na association in our study suggest that the development of breast cancer should not influence the prescribing of 5ARIs therapy.

Smoking and FGFR2 rs2981582 variant independently modulate male breast cancer survival: A population-based study in Tuscany, Italy

AIM

Male breast cancer (MBC) is a rare disease and recommendations for its clinical management are often extrapolated from those for female breast cancer, even if breast cancer (BC) has different characteristics in the two sexes. The purpose of this study was to assess the influence of several individual characteristics including clinico-pathological, lifestyle and genetic factors on overall survival (OS) of a relatively large and well characterized population-based series of 166 MBCs enrolled in Tuscany.

METHODS

We genotyped MBC cases at BRCA1/2 genes and at 9 candidate BC susceptibility SNPs. Kaplan-Meier method and multivariate Cox regression, adjusted for several individual characteristics were used. To reduce a possible selection bias related to the interval between diagnosis and enrolment of MBC cases into the study, we used the date of blood donation as the date of the start of observation for survival analysis.

RESULTS

Only smoking habits had a significant effect on OS at 10 years (for current smokers, HR: 3.34; 95% CI 1.45-7.68; p = 0.004), while lymph node status fell short of reaching statistical significance (for pN positive, HR: 2.07; 95% CI 0.93-4.55; p = 0.07). In the same multivariate analysis we found a significantly higher OS in cases with FGFR2 rs2981582 variant in the dominant transmission model (HR: 0.29; 95% CI: 0.13-0.62; p = 0.028). A sensitivity analysis with left truncation showed similar results.

CONCLUSIONS

Our results may contribute to shed light on factors influencing MBC survival suggesting an important role for cigarette smoking and FGFR2 rs2981582 variant, and provide clues for better patient management.

The cancer genetics and pathology of male breast cancer

Male breast cancer (MBC) is an uncommon and poorly understood disease. Recent molecular studies have shown important differences from female breast cancer which are likely to influence treatment strategies from the current female-based management towards a more tailored approach. Significantly more MBCs than female breast cancers arise with an underlying germline cancer predisposition, and display a vastly different penetrance compared with females. Furthermore, the genophenotypical association of basal-like cancer with BRCA1 present in female breast cancer is not observed in male breast cancer. Differences in somatic changes between male and female breast cancer have also been reported, with particular enrichment of PIK3CA mutations and a paucity of TP53 mutations. In general, chromosomal-based changes, in particular regions of gains, are seen more frequently in male than female breast cancer and methylation is seen less frequently. Clinically, several molecular subtypes with prognostic relevance have been described, including chromosomal complex high and methylation high groups, and subgroups with profiling signatures pertaining to epithelial mesenchymal transition and hormonal therapy insensitivity. As with female breast cancer, attention to male specific multicentre trials based on the individual characteristics are needed, together with establishment of reliable preclinical models to understand more clearly the pathogenesis of male breast cancer and improve the general poor outcome of this disease.

Analysis of Founder Mutations in Rare Tumors Associated With Hereditary Breast/Ovarian Cancer Reveals a Novel Association of BRCA2 Mutations with Ampulla of Vater Carcinomas

BRCA1 and BRCA2 mutations are responsible for hereditary breast and ovarian cancer, but they also confer an increased risk for the development of rarer cancers associated with this syndrome, namely, cancer of the pancreas, male breast, peritoneum, and fallopian tube. The objective of this work was to quantify the contribution of the founder mutations BRCA2 c.156_157insAlu and BRCA1 c.3331_3334del for cancer etiology in unselected hospital-based cohorts of Portuguese patients diagnosed with these rarer cancers, by using a strategy that included testing of archival tumor tissue. A total of 102 male breast, 68 pancreatic and 33 peritoneal/fallopian tube carcinoma cases were included in the study. The BRCA2 c.156_157insAlu mutation was observed with a frequency of 7.8% in male breast cancers, 3.0% in peritoneal/fallopian tube cancers, and 1.6% in pancreatic cancers, with estimated total contributions of germline BRCA2 mutations of 14.3%, 5.5%, and 2.8%, respectively. No carriers of the BRCA1 c.3331_3334del mutation were identified. During our study, a patient with an ampulla of Vater carcinoma was incidentally found to carry the BRCA2 c.156_157insAlu mutation, so we decided to test a consecutive series of additional 15 ampullary carcinomas for BRCA1/BRCA2 mutations using a combination of direct founder mutation testing and full gene analysis with next generation sequencing. BRCA2 mutations were observed with a frequency of 14.3% in ampulla of Vater carcinomas. In conclusion, taking into account the implications for both the individuals and their family members, we recommend that patients with these neoplasias should be offered BRCA1/BRCA2 genetic testing and we here show that it is feasible to test for founder mutations in archival tumor tissue. Furthermore, we identified for the first time a high frequency of germline BRCA2 mutations in ampullary cancers.

Clinical Features of Male Breast Cancer: Experiences from Seven Institutions Over 20 Years

Purpose

Breast cancer treatment has progressed significantly over the past 20 years. However, knowledge regarding male breast cancer (MBC) is sparse because of its rarity. This study is an investigation of the clinicopathologic features, treatments, and clinical outcomes of MBC.

Materials and Methods

Clinical records of 59 MBC patients diagnosed during 1995-2014 from seven institutions in Korea were reviewed retrospectively.

Results

Over a 20-year period, MBC patients accounted for 0.98% among total breast cancer patients, and increased every 5 years. The median age of MBC patientswas 66 years (range, 24 to 87 years). Forty-three patients (73%) complained of a palpable breast mass initially. The median symptom duration was 5 months (range, 1 to 36 months). Mastectomy was performed in 96% of the patients. The most frequent histology was infiltrating ductal carcinoma (75%). Ninety-one percent of tumors (38/43) were estrogen receptor–positive, and 28% (11/40) showed epidermal growth factor receptor 2 (HER-2) overexpression. After curative surgery, 42% of patients (19/45) received adjuvant chemotherapy; 77% (27/35) received hormone therapy. Five out of ten patients with HER-2 overexpressing tumors did not receive adjuvant anti–HER-2 therapy, while two out of four patients with HER-2 overexpressing tumors received palliative trastuzumab for recurrent and metastatic disease. Letrozole was used for one patient in the palliative setting. The median overall survival durations were 7.2 years (range, 0.6 to 17.0 years) in patients with localized disease and 2.9 years (range, 0.6 to 4.3 years) in those with recurrent or metastatic disease.

Conclusion

Anti–HER-2 and hormonal therapy, except tamoxifen, have been underutilized in Korean MBC patients compared to female breast cancer patients. With the development of precision medicine, active treatment with targeted agents should be applied. Further investigation of the unique pathobiology of MBC is clinically warranted.

Male breast cancer in BRCA1 and BRCA2 mutation carriers: pathology data from the Consortium of Investigators of Modifiers of BRCA1/2

BACKGROUND

BRCA1 and, more commonly, BRCA2 mutations are associated with increased risk of male breast cancer (MBC). However, only a paucity of data exists on the pathology of breast cancers (BCs) in men with BRCA1/2 mutations. Using the largest available dataset, we determined whether MBCs arising in BRCA1/2 mutation carriers display specific pathologic features and whether these features differ from those of BRCA1/2 female BCs (FBCs).

METHODS

We characterised the pathologic features of 419 BRCA1/2 MBCs and, using logistic regression analysis, contrasted those with data from 9675 BRCA1/2 FBCs and with population-based data from 6351 MBCs in the Surveillance, Epidemiology, and End Results (SEER) database.

RESULTS

Among BRCA2 MBCs, grade significantly decreased with increasing age at diagnosis (P = 0.005). Compared with BRCA2 FBCs, BRCA2 MBCs were of significantly higher stage (P for trend = 2 × 10(-5)) and higher grade (P for trend = 0.005) and were more likely to be oestrogen receptor-positive [odds ratio (OR) 10.59; 95 % confidence interval (CI) 5.15-21.80] and progesterone receptor-positive (OR 5.04; 95 % CI 3.17-8.04). With the exception of grade, similar patterns of associations emerged when we compared BRCA1 MBCs and FBCs. BRCA2 MBCs also presented with higher grade than MBCs from the SEER database (P for trend = 4 × 10(-12)).

CONCLUSIONS

On the basis of the largest series analysed to date, our results show that BRCA1/2 MBCs display distinct pathologic characteristics compared with BRCA1/2 FBCs, and we identified a specific BRCA2-associated MBC phenotype characterised by a variable suggesting greater biological aggressiveness (i.e., high histologic grade). These findings could lead to the development of gender-specific risk prediction models and guide clinical strategies appropriate for MBC management.

Molecular profiling of male breast cancer - lost in translation?

Breast cancer is the most common cancer form in women and it has been extensively studied on the molecular level. Male breast cancer (MBC), on the other hand, is rare and has not been thoroughly investigated in terms of transcriptional profiles or genomic aberrations. Most of our understanding of MBC has therefore been extrapolated from knowledge of female breast cancer. Although differences in addition to similarities with female breast cancer have been reported, the same prognostic and predictive markers are used to determine optimal management strategies for both men and women diagnosed with breast cancer. This review is focused on prognosis for MBC patients, prognostic and predictive factors and molecular subgrouping; comparisons are made with female breast cancer. Information was collected from relevant literature on both male and female breast cancer from the MEDLINE database between 1992 and 2014. MBC is a heterogeneous disease, and on the molecular level many differences compared to female breast cancer have recently been revealed. Two distinct subgroups of MBC, luminal M1 and luminal M2, have been identified which differ from the well-established intrinsic subtypes of breast cancer in women. These novel subgroups of breast cancer therefore appear unique to MBC. Furthermore, several studies report inferior survival for men diagnosed with breast cancer compared to women. New promising prognostic biomarkers for MBC (e.g. NAT1) deserving further attention are reviewed. Further prospective studies aimed at validating the novel subgroups and recently proposed biomarkers for MBC are warranted to provide the basis for optimal patient management in this era of personalized medicine. This article is part of a Directed Issue entitled: Rare Cancers.

Male breast cancer: genetics, epigenetics, and ethical aspects

BACKGROUND AND STUDY DESIGN

Male breast cancer (MBC) is a rare disease compared with female BC and our current understanding regarding breast carcinogenesis in men has been largely extrapolated from the female counterpart. We focus on differences between the ethical issues related to male and female BC patients. A systematic literature search by using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/), was carried out to provide a synopsis of the current research in the field of MBC genetics, epigenetics and ethics. Original articles and reviews published up to September 2012 were selected by using the following search key words to query the PubMed website: 'male breast cancer', 'male breast cancer and genetic susceptibility', 'male breast cancer and epigenetics', 'male breast cancer and methylation', 'male breast cancer and miRNA', 'male breast cancer and ethics'.

RESULTS AND CONCLUSIONS

As in women, three classes of breast cancer genetic susceptibility (high, moderate, and low penetrance) are recognized in men. However, genes involved and their impact do not exactly overlap in female and male BC. Epigenetic alterations are currently scarcely investigated in MBC, however, the different methylation and miRNA expression profiles identified to date in female and male BCs suggest a potential role for epigenetic alterations as diagnostic biomarkers. Overall, much still needs to be learned about MBC and, because of its rarity, the main effort is to develop large consortia for moving forward in understanding MBC and improving the management of MBC patients on a perspective of gender medicine.

SULT1A1 gene deletion in BRCA2-associated male breast cancer: a link between genes and environmental exposures?

SULT1A1, a member of sulfotransferase superfamily, is a drug and hormone metabolizing enzyme involved in the metabolism of a variety of potential mammary carcinogens of endogenous and exogenous origin. Interestingly, the metabolic activity of SULT1A1 can be affected by variations in gene copy number. Male Breast Cancer (MBC) is a rare disease and less investigated disease compared to female BC (FBC). As in FBC, the concurrent effects of genetic risk factors, particularly BRCA2 mutations, increased exposure to estrogens and environmental carcinogens play a relevant role in MBC. By quantitative real-time PCR with TaqMan probes, we investigated the presence of SULT1A1 gene copy number variations (CNVs) in a series of 72 MBCs. SULT1A1 gene deletion was observed in 10 of the 72 MBCs (13.9%). In a multivariate analysis association between BRCA2 mutation and SULT1A1 gene deletion emerged (p = 0.0005). Based on the evidence that the level of SULT1A1 enzyme activity is correlated with CNV, our data suggest that in male breast tumors SULT1A1 activity may be decreased. Thus, it can be hypothesized that in a proportion of MBCs, particularly in BRCA2-associated MBCs, the level of estrogens and environmental carcinogens exposure might be increased suggesting a link between gene and environmental exposure in the pathogenesis of MBC.

An update on male breast cancer and future directions for research and treatment

Male breast cancer is a rare disease for which treatment has been based on the evidence available from female breast cancer. The new genomic tools can better characterize the biology of breast cancer. It is hoping that these will help to clarify possible differences of breast cancer behaviour in male patients, which will have a major impact on treatment strategies and on the conduct of clinical trials in this setting. In this review we will summarize available information on epidemiology, risk factors for breast cancer in men, the new insights of the biology of this disease, current recommendations for treatment and insights for future research.

Male breast cancer: risk factors, biology, diagnosis, treatment, and survivorship

BACKGROUND

The causes, optimal treatments, and medical/psychosocial sequelae of breast cancer in men are poorly understood.

DESIGN

A systematic review of the English language literature was conducted to identify studies relevant to male breast cancer between 1987 and 2012 and including at least 20 patients. Searches were carried out on PubMed using the title terms 'male breast cancer' or 'male breast carcinoma'.

RESULTS

Relevant published data regarding risk factors, biological characteristics, presentation and prognosis, appropriate evaluation and treatment, and survivorship issues in male breast cancer patients are presented. BRCA2 mutations, age, conditions that alter the estrogen/androgen ratio, and radiation are proven risk factors. Disease biology is distinct in men, but diagnostic approaches and treatments for men are generally extrapolated from those in women due to inadequate research in men. Survivorship issues in men may include sexual and hormonal side-effects of endocrine therapies as well as unique psychosocial impacts of the disease.

CONCLUSION

Further research is needed to address gaps in knowledge pertaining to care of male breast cancer patients and survivors.

PIK3CA mutations are frequently observed in BRCAX but not BRCA2-associated male breast cancer

INTRODUCTION

Although a substantial proportion of male breast cancers (MBCs) are hereditary, the molecular pathways that are activated are unknown. We therefore examined the frequency and clinicopathological associations of the PIK3CA/mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) pathways and their regulatory genes in familial MBC.

METHODS

High resolution melting analysis and confirmatory sequencing was used to determine the presence of somatic mutations in PIK3CA (exon 9 and 20), AKT1 (exon 4), KRAS (exon 2) and BRAF (exon 15) genes in 57 familial MBCs. Further analysis of the PIK3CA/mTOR pathway was performed using immunohistochemistry for the pAKT1, pS6 and p4EBP1 biomarkers.

RESULTS

PIK3CA somatic mutations were identified in 10.5% (6 of 57) of cases; there were no AKT1, KRAS or BRAF somatic mutations. PIK3CA mutations were significantly more frequent in cancers from BRCAX patients (17.2%, 5/29) than BRCA2 (0%, 0/25) carriers (P = 0.030). Two BRCAX patients had an E547K mutation which has only been reported in one female breast cancer previously. PIK3CA mutation was significantly correlated with positive pS6 (83.3% vs. 32.0%, P = 0.024) and negative p4EBP1 (100% vs. 38.0%, P = 0.006) expression, but not pAKT expression. Expression of nuclear p4EBP1 correlated with BRCA2 mutation carrier status (68.0% vs. 38.7%, P = 0.035).

CONCLUSIONS

Somatic PIK3CA mutation is present in familial male breast cancer but absent in BRCA2 carriers. The presence of two of the extremely rare E547K PIK3CA mutations in our cohort may have specific relevance in MBCs. Further study of PIK3CA in MBCs, and in particular BRCAX patients, may contribute to further establishing the relevance of specific PIK3CA mutations in MBC aetiology and in the identification of particular patient groups most likely to benefit from therapeutic targeting with the novel PIK3CA inhibitors that are currently in development.

Genotypic and phenotypic analysis of familial male breast cancer shows under representation of the HER2 and basal subtypes in BRCA-associated carcinomas

Background

Male breast cancer (MBC) is an uncommon and relatively uncharacterised disease accounting for <1% of all breast cancers. A significant proportion occurs in families with a history of breast cancer and in particular those carrying BRCA2 mutations. Here we describe clinicopathological features and genomic BRCA1 and BRCA2 mutation status in a large cohort of familial MBCs.

Methods

Cases (n=60) included 3 BRCA1 and 25 BRCA2 mutation carries, and 32 non-BRCA1/2 (BRCAX) carriers with strong family histories of breast cancer. The cohort was examined with respect to mutation status, clinicopathological parameters including TNM staging, grade, histological subtype and intrinsic phenotype.

Results

Compared to the general population, MBC incidence was higher in all subgroups. In contrast to female breast cancer (FBC) there was greater representation of BRCA2 tumours (41.7% vs 8.3%, p=0.0008) and underrepresentation of BRCA1 tumours (5.0% vs 14.4%, p=0.0001). There was no correlation between mutation status and age of onset, disease specific survival (DSS) or other clincopathological factors. Comparison with sporadic MBC studies showed similar clinicopathological features. Prognostic variables affecting DSS included primary tumour size (p=0.003, HR:4.26 95%CI 1.63-11.11), age (p=0.002, HR:4.09 95%CI 1.65-10.12), lymphovascular (p=0.019, HR:3.25 95%CI 1.21-8.74) and perineural invasion (p=0.027, HR:2.82 95%CI 1.13-7.06). Unlike familial FBC, the histological subtypes seen in familial MBC were more similar to those seen in sporadic MBC with 46 (76.7%) pure invasive ductal carcinoma of no special type (IDC-NST), 2 (3.3%) invasive lobular carcinomas and 4 (6.7%) invasive papillary carcinoma. A further 8 (13.3%) IDC-NST had foci of micropapillary differentiation, with a strong trend for co-occurrence in BRCA2 carriers (p=0.058). Most tumours were of the luminal phenotype (89.7%), with infrequent HER2 (8.6%) and basal (1.7%) phenotype tumours seen.

Conclusion

MBC in BRCA1/2 carriers and BRCAX families is different to females. Unlike FBC, a clear BRCA1 phenotype is not seen but a possible BRCA2 phenotype of micropapillary histological subtype is suggested. Comparison with sporadic MBCs shows this to be a high-risk population making further recruitment and investigation of this cohort of value in further understanding these uncommon tumours.

Accuracy of BRCA1/2 mutation prediction models for different ethnicities and genders: experience in a southern Chinese cohort

Background

BRCA1/2 mutation prediction models (BRCAPRO, Myriad II, Couch, Shattuck-Eidens, BOADICEA) are well established in western cohorts to estimate the probability of BRCA1/2 mutations. Results are conflicting in Asian populations. Most studies did not account for gender-specific prediction. We evaluated the performance of these models in a Chinese cohort, including males, before BRCA1/2 mutation testing.

Methods

The five risk models were used to calculate the probability of BRCA mutations in probands with breast and ovarian cancers; 267 were non-BRCA mutation carriers (247 females and 20 males) and 43 were BRCA mutation carriers (38 females and 5 males).

Results

Mean BRCA prediction scores for all models were statistically better for carriers than noncarriers for females but not for males. BRCAPRO overestimated the numbers of female BRCA1/2 mutation carriers at thresholds ≥20% but underestimated if <20%. BRCAPRO and BOADICEA underestimated the number of male BRCA1/2 mutation carriers whilst Myriad II underestimated the number of both male and female carriers. In females, BRCAPRO showed similar discrimination, as measured by the area under the receiver operator characteristic curve (AUC) for BRCA1/2 combined mutation prediction to BOADICEA, but performed better than BOADICEA in BRCA1 mutation prediction (AUC 93% vs. 87%). BOADICEA had the best discrimination for BRCA1/2 combined mutation prediction (AUC 87%) in males.

Conclusions

The variation in model performance underscores the need for research on larger Asian cohorts as prediction models, and the possible need for customizing these models for different ethnic groups and genders.

Clinical and pathologic characteristics of BRCA-positive and BRCA-negative male breast cancer patients: results from a collaborative multicenter study in Italy

Recently, the number of studies on male breast cancer (MBC) has been increasing. However, as MBC is a rare disease there are difficulties to undertake studies to identify specific MBC subgroups. At present, it is still largely unknown whether BRCA-related breast cancer (BC) in men may display specific characteristics as it is for BRCA-related BC in women. To investigate the clinical-pathologic features of MBC in association with BRCA mutations we established a collaborative Italian Multicenter Study on MBC with the aim to recruit a large series of MBCs. A total of 382 MBCs, including 50 BRCA carriers, were collected from ten Italian Investigation Centres covering the whole country. In MBC patients, BRCA2 mutations were associated with family history of breast/ovarian cancer (p<0.0001), personal history of other cancers (p=0.044) and contralateral BC (p=0.001). BRCA2-associated MBCs presented with high tumor grade (p=0.001), PR-(p=0.026) and HER2+ (p=0.001) status. In a multivariate logistic model BRCA2 mutations showed positive association with personal history of other cancers (OR 11.42, 95% CI 1.79-73.08) and high tumor grade (OR 4.93, 95% CI 1.02-23.88) and inverse association with PR+ status (OR 0.19, 95% CI 0.04-0.92). Based on immunohistochemical (IHC) profile, four molecular subtypes of MBC were identified. Luminal A was the most common subtype (67.7%), luminal B was observed in 26.5% of the cases and HER2 positive and triple negative were represented by 2.1% and 3.7% of tumors, respectively. Intriguingly, we found that both luminal B and HER2 positive subtypes were associated with high tumor grade (p=0.003 and 0.006, respectively) and with BRCA2 mutations (p=0.016 and 0.001, respectively). In conclusion, our findings indicate that BRCA2-related MBCs represent a subgroup of tumors with a peculiar phenotype characterized by aggressive behavior. The identification of a BRCA2-associated phenotype might define a subset of MBC patients eligible for personalized clinical management.

Gene expression profiling of primary male breast cancers reveals two unique subgroups and identifies N-acetyltransferase-1 (NAT1) as a novel prognostic biomarker

INTRODUCTION

Male breast cancer (MBC) is a rare and inadequately characterized disease. The aim of the present study was to characterize MBC tumors transcriptionally, to classify them into comprehensive subgroups, and to compare them with female breast cancer (FBC).

METHODS

A total of 66 clinicopathologically well-annotated fresh frozen MBC tumors were analyzed using Illumina Human HT-12 bead arrays, and a tissue microarray with 220 MBC tumors was constructed for validation using immunohistochemistry. Two external gene expression datasets were used for comparison purposes: 37 MBCs and 359 FBCs.

RESULTS

Using an unsupervised approach, we classified the MBC tumors into two subgroups, luminal M1 and luminal M2, respectively, with differences in tumor biological features and outcome, and which differed from the intrinsic subgroups described in FBC. The two subgroups were recapitulated in the external MBC dataset. Luminal M2 tumors were characterized by high expression of immune response genes and genes associated with estrogen receptor (ER) signaling. Luminal M1 tumors, on the other hand, despite being ER positive by immunohistochemistry showed a lower correlation to genes associated with ER signaling and displayed a more aggressive phenotype and worse prognosis. Validation of two of the most differentially expressed genes, class 1 human leukocyte antigen (HLA) and the metabolizing gene N-acetyltransferase-1 (NAT1), respectively, revealed significantly better survival associated with high expression of both markers (HLA, hazard ratio (HR) 3.6, P = 0.002; NAT1, HR 2.5, P = 0.033). Importantly, NAT1 remained significant in a multivariate analysis (HR 2.8, P = 0.040) and may thus be a novel prognostic marker in MBC.

CONCLUSIONS

We have detected two unique and stable subgroups of MBC with differences in tumor biological features and outcome. They differ from the widely acknowledged intrinsic subgroups of FBC. As such, they may constitute two novel subgroups of breast cancer, occurring exclusively in men, and which may consequently require novel treatment approaches. Finally, we identified NAT1 as a possible prognostic biomarker for MBC, as suggested by NAT1 positivity corresponding to better outcome.

Inherited and acquired alterations in development of breast cancer

Breast cancer is the most common cancer among women, accounting for about 30% of all cancers. In contrast, breast cancer is a rare disease in men, accounting for less than 1% of all cancers. Up to 10% of all breast cancers are hereditary forms, caused by inherited germ-line mutations in "high-penetrance," "moderate-penetrance," and "low-penetrance" breast cancer susceptibility genes. The remaining 90% of breast cancers are due to acquired somatic genetic and epigenetic alterations. A heterogeneous set of somatic alterations, including mutations and gene amplification, are reported to be involved in the etiology of breast cancer. Promoter hypermethylation of genes involved in DNA repair and hormone-mediated cell signaling, as well as altered expression of micro RNAs predicted to regulate key breast cancer genes, play an equally important role as genetic factors in development of breast cancer. Elucidation of the inherited and acquired genetic and epigenetic alterations involved in breast cancer may not only clarify molecular pathways involved in the development and progression of breast cancer itself, but may also have an important clinical and therapeutic impact on improving the management of patients with the disease.

The occurrence of germline BRCA1 and BRCA2 sequence alterations in Slovenian population

BACKGROUND

the BRCA1 and BRCA2 mutation spectrum and mutation detection rates according to different family histories were investigated in 521 subjects from 322 unrelated Slovenian cancer families with breast and/or ovarian cancer.

METHODS

the BRCA1 and BRCA2 genes were screened using DGGE, PTT, HRM, MLPA and direct sequencing.

RESULTS

eighteen different mutations were found in BRCA1 and 13 in BRCA2 gene. Mutations in one or other gene were found in 96 unrelated families. The mutation detection rates were the highest in the families with at least one breast and at least one ovarian cancer - 42% for BRCA1 and 8% for BRCA2. The mutation detection rate observed in the families with at least two breast cancers with disease onset before the age of 50 years and no ovarian cancer was 23% for BRCA1 and 13% for BRCA2. The mutation detection rate in the families with at least two breast cancers and only one with the disease onset before the age of 50 years was 11% for BRCA1 and 8% for BRCA2. In the families with at least two breast cancers, all of them with disease onset over the age of 50 years, the detection rate was 5% for BRCA2 and 0% for BRCA1.

CONCLUSION

among the mutations detected in Slovenian population, 5 mutations in BRCA1 and 4 mutations in BRCA2 have not been described in other populations until now. The most frequent mutations in our population were c.181T > G, c.1687C > T, c.5266dupC and c.844_850dupTCATTAC in BRCA1 gene and c.7806-2A > G, c.5291C > G and c.3978insTGCT in BRCA2 gene (detected in 69% of BRCA1 and BRCA2 positive families).

Mutation analysis of BRIP1 in male breast cancer cases: a population-based study in Central Italy

Breast cancer (BC) in men is rare compared with BC in women, but its incidence is increasing along with attention toward this uncommon disease. Although with some differences, male and female BC share similar genetic predisposition factors, including BRCA1/2, CHEK2, and PALB2 mutations. As other BRCA1/2 functionally related DNA repair genes, such as CHEK2 and PALB2, BRIP1 is considered a moderate-penetrance BC susceptibility gene. At present, the role of BRIP1 on BC susceptibility in men is unknown. In this study, we aimed to assess whether BRIP1 variants may contribute to male BC (MBC) risk, by screening 97 MBC cases, all negative for BRCA1/2, CHEK2, and PALB2 mutations, selected from a population-based series of 126 MBCs from Central Italy. A total of five BRIP1 germ-line sequence alterations, three coding, and two non-coding variants, were detected in our series. The two non-coding variants IVS4-28G > A and 3'UTR 4049C > T were classified as neutral by in silico analysis. Of the three coding variants, one was a silent variant (E879E) and two resulted in amino acid substitution (R264W and P919S) showing a putative pathogenic role by in silico analysis. However, further analysis of tumor-associated loss of heterozygosity and the frequency of variant alleles, tested in 203 male population controls, suggested a neutral effect for both of these variants. Overall, our results indicate that BRIP1 variants may not play a relevant role in MBC predisposition.

High-resolution genomic profiling of male breast cancer reveals differences hidden behind the similarities with female breast cancer

Male breast cancer (MBC) is extremely rare and poorly characterized on the molecular level. Using high-resolution genomic data, we aimed to characterize MBC by genomic imbalances and to compare it with female breast cancer (FBC), and further to investigate whether the genomic profiles hold any prognostic information. Fifty-six fresh frozen MBC tumors were analyzed using high-resolution tiling BAC arrays. Significant regions in common between cases were assessed using Genomic Identification of Significant Targets in Cancer (GISTIC) analysis. A publicly available genomic data set of 359 FBC tumors was used for reference purposes. The data revealed a broad pattern of aberrations, confirming that MBC is a heterogeneous tumor type. Genomic gains were more common in MBC than in FBC and often involved whole chromosome arms, while losses of genomic material were less frequent. The most common aberrations were similar between the genders, but high-level amplifications were more common in FBC. We identified two genomic subgroups among MBCs; male-complex and male-simple. The male-complex subgroup displayed striking similarities with the previously reported luminal-complex FBC subgroup, while the male-simple subgroup seems to represent a new subgroup of breast cancer occurring only in men. There are many similarities between FBC and MBC with respect to genomic imbalances, but there are also distinct differences as revealed by high-resolution genomic profiling. MBC can be divided into two comprehensive genomic subgroups, which may be of prognostic value. The male-simple subgroup appears notably different from any genomic subgroup so far defined in FBC.

Mutations in BRCA2 and PALB2 in male breast cancer cases from the United States

Male breast cancer (MBC) is an uncommon disease with a frequency of approximately one in 1000. Due to the rarity of MBC, it is understudied and its etiology is poorly understood. Our objectives are to determine the frequency of pathogenic mutations in BRCA2 and PALB2 in MBC cases and to investigate the correlations between mutation status and cancer phenotypes. Single strand conformation polymorphism analysis, direct sequencing, and multiplex ligation-dependent probe amplification were employed to screen for mutations in the BRCA2 gene, followed by direct sequencing of the PALB2 gene in BRCA2-negative MBC cases. Pathogenic BRCA2 mutations were identified in 18 of the 115 MBC cases, including four of the ten cases (40%) from breast cancer families and 14 of the 105 cases (13%) unselected for family history of breast cancer. The difference in BRCA2-mutation frequencies between cases with and without family history of breast cancer was not statistically significant (P = 0.145), suggesting that family history is not a strong predictor of carrying a mutation in males. We observed a highly significant association of carrying a pathogenic BRCA2 mutation with high tumor grade (P < 0.001) and a weak association with positive lymph nodes (P < 0.02). Of the 97 BRCA2-negative MBC cases, we identified one PALB2 mutation with confirmed pathogenicity and one mutation predicted to be pathogenic, a prevalence of pathogenic PALB2-mutation of 1-2%. Based on our results and previous studies, genetic testing for BRCA2 should be recommended for any diagnosed MBC case, regardless of family history of breast cancer.

HER2-positive male breast cancer: an update

Although rare, male breast cancer (MBC) remains a substantial cause for morbidity and mortality in men. Based on age frequency distribution, age-specific incidence rate pattern, and prognostic factor profiles, MBC is considered similar to postmenopausal breast cancer (BC). Compared with female BC (FBC), MBC cases are more often hormonal receptor (estrogen receptor/progesterone receptor [ER/PR]) positive and human epidermal growth factor receptor 2 (HER2) negative. Treatment of MBC patients follows the same indications as female postmenopausal with surgery, systemic therapy, and radiotherapy. To date, ER/PR and HER2 status provides baseline predictive information used in selecting optimal adjuvant/neoadjuvant therapy and in the selection of therapy for recurrent or metastatic disease. HER2 represents a very interesting molecular target and a number of compounds (trastuzumab [Herceptin®; F. Hoffmann-La Roche, Basel, Switzerland] and lapatinib [Tykerb®, GlaxoSmithKline, London, UK]) are currently under clinical evaluation. Particularly, trastuzumab, a monoclonal antibody which selectively binds the extracellular domain of HER2, has become an important therapeutic agent for women with HER2-positive (HER2+) BC. Currently, data regarding the use of trastuzumab in MBC patients is limited and only few case reports exist. In all cases, MBC patients received trastuzumab concomitantly with other drugs and no severe toxicity above grade 3 was observed. However, MBC patients that would be candidate for trastuzumab therapy (ie, HER2+/ER+ or HER2+/ER- MBCs) represent only a very small percentage of MBC cases. This is noteworthy, when taking into account that trastuzumab is an important and expensive component of systemic BC therapy. Since there is no data supporting the fact that response to therapy is different for men or women, we concluded that systemic therapy in MBC should be considered on the same basis as for FBC. Particularly in male patients, trastuzumab should be considered exclusively for advanced disease or high-risk HER2+ early BCs. On the other hand, lapatinib (Tykerb), a novel oral dual tyrosine kinase inhibitor that targets both HER2 and epidermal growth factor receptor, may represent an interesting and promising therapeutic agent for trastuzumab-resistant MBC patients.

The BRCAPRO 5.0 model is a useful tool in genetic counseling and clinical management of male breast cancer cases

No study has evaluated the performance of BRCA1/2 mutations prediction models in male breast cancer (MBC) series. Although rare, MBC deserves attention because male and female breast cancers share many characteristics, including the involvement of genetic predisposition factors such as BRCA1/BRCA2 mutations. Indeed, the occurrence of MBC is a commonly used criterion to select families for BRCA mutation testing. We evaluated the performance and clinical effectiveness of four different predictive models in a population-based series of 102 Italian MBC patients characterized for BRCA1/2 mutations. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated for each risk model at the 10% threshold. The area under the ROC (AUC) curves and its corresponding asymptotic 95% CIs were calculated as a measure of the accuracy. In our study, the BRCAPRO version 5.0 had the highest combination of sensitivity, specificity, NPV and PPV for the combined probability and for the discrimination of BRCA2 mutations. In individuals with negative breast-ovarian cancer family history, BRCAPRO 5.0 reached a high discriminatory capacity (AUC=0.92) in predicting BRCA2 mutations and showed values of sensitivity, specificity, NPV and PPV of 0.5, 0.98, 0.97 and 0.67, respectively, for the combined probability. BRCAPRO version 5.0 can be particularly useful in dealing with non-familial MBC, a circumstance that often represents a challenging situation in genetic counseling.

Male breast cancer: a population-based comparison with female breast cancer

PURPOSE

Because of its rarity, male breast cancer is often compared with female breast cancer.

PATIENTS AND METHODS

To compare and contrast male and female breast cancers, we obtained case and population data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program for breast cancers diagnosed from 1973 through 2005. Standard descriptive epidemiology was supplemented with age-period-cohort models and breast cancer survival analyses.

RESULTS

Of all breast cancers, men with breast cancer make up less than 1%. Male compared with female breast cancers occurred later in life with higher stage, lower grade, and more estrogen receptor-positive tumors. Recent breast cancer incidence and mortality rates declined over time for men and women, but these trends were greater for women than for men. Comparing patients diagnosed from 1996 through 2005 versus 1976 through 1985, and adjusting for age, stage, and grade, cause-specific hazard rates for breast cancer death declined by 28% among men (P = .03) and by 42% among women (P approximately 0).

CONCLUSION

There were three intriguing results. Age-specific incidence patterns showed that the biology of male breast cancer resembled that of late-onset female breast cancer. Similar breast cancer incidence trends among men and women suggested that there are common breast cancer risk factors that affect both sexes, especially estrogen receptor-positive breast cancer. Finally, breast cancer mortality and survival rates have improved significantly over time for both male and female breast cancer, but progress for men has lagged behind that for women.