HER2-positive male breast cancer: an update

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.

Single-cell transcriptome analysis indicates fatty acid metabolism-mediated metastasis and immunosuppression in male breast cancer

Male breast cancer (MBC) is a rare but aggressive malignancy with cellular and immunological characteristics that remain unclear. Here, we perform transcriptomic analysis for 111,038 single cells from tumor tissues of six MBC and thirteen female breast cancer (FBC) patients. We find that that MBC has significantly lower infiltration of T cells relative to FBC. Metastasis-related programs are more active in cancer cells from MBC. The activated fatty acid metabolism involved with FASN is related to cancer cell metastasis and low immune infiltration of MBC. T cells in MBC show activation of p38 MAPK and lipid oxidation pathways, indicating a dysfunctional state. In contrast, T cells in FBC exhibit higher expression of cytotoxic markers and immune activation pathways mediated by immune-modulatory cytokines. Moreover, we identify the inhibitory interactions between cancer cells and T cells in MBC. Our study provides important information for understanding the tumor immunology and metabolism of MBC.

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.

Management of Male Breast Cancer: The Journey so Far and Future Directions

Male breast cancer is now shown to be a unique entity and should be considered as a distinct disease. Given the relatively smaller number of cases, randomized controlled trials for treatment are extremely limited and majority of practices are derived from female breast cancer studies. This paper reviews available literature on surgical, radiation, and systemic therapies for male breast cancer, and discusses current practice recommendations.

Poor prognosis of male triple-positive breast Cancer patients: a propensity score matched SEER analysis and molecular portraits

Background

The purpose of this study was to explore clinicalpathology features, molecular features and outcome of male breast cancer patients who expressed ER, PR as well as HER-2, namely triple-positive male breast cancer (TP-MBC), and compared them with triple-positive female breast cancer patients (TP-FBC).

Methods

TP-MBC and TP-FBC from 2010 to 2017 were selected from the Surveillance, Epidemiology, and End Results database (SEER). Kaplan-Meier plotter and multivariable Cox regression model were applied to analyse the difference between TP-MBC and TP-FBC on cancer-specific survival (CSS) and overall survival (OS). Propensity score matched (PSM) analysis was used to ensure well-balanced characteristics. 7 cases TP-MBC and 174 cases TP-FBC patients with the genomic and clinical information were identified from the cohort of The Cancer Genome Atlas (TCGA) and the Memorial Sloan Kettering (MSK).

Result

336 TP-MBC and 33,339 TP-FBC patients were taken into the study. The percentages of TP-MBC in MBC patients were higher than the rates of TP-FBC in FBC patients from 2010 to 2017 except 2012. Compared with TP-FBC, more TP-MBC were staged III (17.9% vs. 13.5%) or stage IV (11.0% vs. 6.9%). TP-MBC were more frequently to be older than 65-years-old (47.0% vs. 29.3%), Balck (15.2% vs. 10.8%), ductal carcinoma (91.7% vs. 84.4%) and metastases to lung (4.5% vs. 2.1%) or bone (8.6% vs. 4.7%). TP-MBC had worse OS and CSS than TP-FBC in all stages (P < 0.001). In multivariable prediction model of TPBC, male patients had a higher risk than female. Lastly, the worse OS (P < 0.001) and CSS (P = 0.013) were seen in the 1:3 PSM analysis between TP-MBC and TP-FBC. Genomic analysis revealed that TP-MBCs have some notable rare mutations, like ERBB2, ERBB3, RB1, CDK12, FGFR2, IDH1, AGO2, GATA3, and some of them are not discovered in TP-FBC.

Conclusion

TP-MBC had a worse survival than TP-FBC, and there were different genomic features between two groups. Current knowledge and treatment to TP-MBC maybe inadequate and remain to be explored.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08267-9.

An updated review of epidemiology, risk factors, and management of male breast cancer

Unlike female breast cancer, male breast cancer (MBC) is rare and not very well understood. Prospective data in the management of MBC are lacking and majority of treatment strategies are adopted from the established guidelines for breast cancer in women. The understanding of biology, clinical presentation, genetics, and management of MBC is evolving but there still remains a large knowledge gap due to the rarity of this disease. Older age, high estradiol levels, klinefelter syndrome, radiation exposure, gynecomastia, family history of breast cancer, BRCA2 and BRCA1 mutation are some of the known risk factors for MBC. Routine screening mammography is not recommended for asymptomatic men. Diagnostic mammogram with or without ultrasound should be considered if there is a suspicion for breast mass. Majority of men with early-stage breast cancer undergo mastectomy whereas breast conserving surgery (BCS) with sentinel lymph node biopsy (SLNB) remains an alternative option in selected cases. Since the majority of MBC are hormone receptor positive (HR+), adjuvant hormonal therapy is required. Tamoxifen for a total of 5 to 10 years is the mainstay adjuvant hormonal therapy. The role of neoadjuvant and adjuvant chemotherapy for early-stage breast cancer is uncertain and not commonly used. The role of gene recurrence scores like oncotype Dx and mammaprint is evolving and can be used as an aid for adjuvant chemotherapy. Majority of metastatic MBC are treated with hormonal therapy with either tamoxifen, gonadotropin-releasing hormone agonist (GnRH) with aromatase inhibitors (AI), or fulvestrant. Chemotherapy is reserved for patients with visceral crisis or rapidly growing tumors.

Survival benefit of tamoxifen in male breast cancer: prospective cohort analysis

Background

Due to the lack of prospective data, current treatment of male breast cancer (MBC) is based on information obtained from retrospective analysis or by extrapolation from studies on female patients. In this prospectively enrolled cohort study, we retrospectively examined the survival effect of tamoxifen in MBC patients.

Methods

In this prospectively enrolled cohort study, 448 patients with MBC were treated between May 2009 and June 2018. The primary endpoint was disease-free survival (DFS).

Results

Between May 2009 and June 2018, 448 men with breast cancer were identified, with a median age at diagnosis of 69 years (range 27–96 years). The median follow-up was 39 months (range 3–89 months). Most tumours were larger than 20 mm; invasive ductal carcinoma was of no special histological type and with an intermediate grade of differentiation. Almost half of the men were diagnosed with positive axillary lymph nodes (43.5%). Hormone receptor (HR) positivity was observed in 98.4% of the patients. Notably, DFS among men who did not receive tamoxifen was significantly reduced as compared with those who underwent tamoxifen therapy (P = 0.002). The recurrence rate and mortality in the group of patients without and with tamoxifen treatment were 18.2% and 11.2%, respectively. The most common localisation of metastases was the bone. After adjustment for prognostic factors, we found that tamoxifen was found to reduce the recurrence rate by 68% (hazard ratio HR = 0.32; 95% confidence interval, CI: 0.14–0.74).

Conclusions

Tamoxifen treatment was associated with improved DFS for MBC patients.

Clinical trial registration

DRKS00009536.

Male Breast Cancer: Reevaluate Our Opinion

Male breast cancers (MBCs) are relatively uncommon malignancy with less than 1% incidence. MBC presents at a later age with a more advanced presentation as compared to the female breast cancer. Due to the paucity of the number of cases and trials regarding the MBC, female breast cancer treatment protocols are applied. Mastectomy and hormonal therapy remains the mainstay of treatment. Moreover, the data about prognosis of MBC remains limited.

BRCA2 genemutation, c.2808_2811delACAA (p.Ala938Profs), in malebreastcancer - clinicopathologicalanalysisbased on a case report

Male breast cancer (MBC) is a rare disease that occurs in ~0.2% of all neoplasms among men. The risk of developing MBC is higher in men with a BRCA2 genetic mutation (7%). The aim of this study was to evaluate the association between c.2808_2811del ACAA (p.Ala938Profs) BRCA2 mutation in MBC and clinicopathological factors. A 75-year-old patient was admitted to the Genetic Outpatient Clinic with a diagnosis of right breast cancer and with a family history of cancer (two daughters who were diagnosed with breast cancer at ages 46 and 38 years). Postoperative histopathological examination revealed tumor type pT2 N1a Mx, NST NG-3 G-3, Ki-67 (75%), HER2 (+), ER (+++), PR (+++), invasive carcinoma and luminal B subtype. The complete coding sequences of the BRCA1 and BRCA2 genes were analyzed for genomic DNA material using next generation sequencing on the Ion Torrent platform. The c.2808_2811delACAA (p.Ala938Profs) mutation was observed in the BRCA2 gene. The presence of the c.2808_2811delACAA (p.Ala938Profs) mutation in the BRCA2 gene was confirmed using the Sanger method. The same BRCA2 gene mutation was reported in one of the patient's daughters. The detected mutation causes the frameshift mutation, resulting in the creation of an additional translation termination codon and the synthesis of an abnormal protein. This mutation was associated with a later age of disease, a higher histological degree, a higher mitotic index, a positive steroid receptor status and the luminal B subtype HER2- breast cancer.

Effects of HER2 status on the prognosis of male breast cancer: a population-based study

Objective

This study was designed to analyze the effects of human epidermal growth factor receptor-2 (HER2) status on the prognosis of male breast cancer (MBC).

Methods

The SEER database was used to identify MBC patients diagnosed between 2010 and 2015. Patients were divided into HER2-negative and HER2-positive groups and chi-square test was used to compare the demographics. Propensity score matching (PSM) was used to remove confounding factors. The log-rank test was used to compare the overall survival (OS) and disease-specific survival (DSS) between the two groups. Univariate and multivariate Cox regression analyses were used to evaluate the effects of different variables on the prognosis of MBC patients. Subgroup analysis was conducted by using R software to explore the benefit of OS and DSS in the subgroup of MBC patients.

Results

In the matched cohort, the log-rank test showed that there was a longer OS (P=0.044) in the HER2-negative group, and the 4-year OS rate in HER2-negative patients was significantly improved (P=0.008), but there was no difference in the DSS (P=0.408) and the 4-year DSS rates (P=0.198) between the two groups. Univariate and multivariate Cox regression also showed that the HER2 status did not independently associate with DSS (P=0.444). Subgroup analysis showed that HER2-negative patients experienced a longer OS in the subgroup of tumors 2–4 cm in size, no distant metastasis and who had received radiotherapy, but none of subgroup was found a significant difference in DSS between different HER2 status.

Conclusion

This study identified that HER2 status had a clear influence on OS in patients with MBC, and there was a longer OS and a higher 4-year OS rate in the HER2-negative group. In addition, we observed that HER2 status had no significant effect on DSS in patients with MBC.

Somatic alterations of targetable oncogenes are frequently observed in BRCA1/2 mutation negative male breast cancers

Male breast cancer (MBC) is a rare disease. Due to its rarity, MBC research and clinical approach are mostly based upon data derived from its largely known female counterpart. We aimed at investigating whether MBC cases harbor somatic alterations of genes known as prognostic biomarkers and molecular therapeutic targets in female breast cancer.

We examined 103 MBC cases, all characterized for germ-line BRCA1/2 mutations, for somatic alterations in PIK3CA, EGFR, ESR1 and CCND1 genes.

Pathogenic mutations of PIK3CA were detected in 2% of MBCs. No pathogenic mutations were identified in ESR1 and EGFR. Gene copy number variations (CNVs) analysis showed amplification of PIK3CA in 8.1%, EGFR in 6.8% and CCND1 in 16% of MBCs, whereas deletion of ESR1 was detected in 15% of MBCs. Somatic mutations and gene amplification were found only in BRCA1/2 mutation negative MBCs.

Significant associations emerged between EGFR amplification and large tumor size (T4), ER-negative and HER2-positive status, between CCND1 amplification and HER2-positive and MIB1-positive status, and between ESR1 deletion and ER-negative status.

Our results show that amplification of targetable oncogenes is frequent in BRCA1/2 mutation negative MBCs and may identify MBC subsets characterized by aggressive phenotype that may benefit from potential targeted therapeutic approaches.

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.

[Prevalence of male breast cancer in our department during a 5-year period]

Male breast cancer is a rare entity. Statistics suggest the female:male ratio is100:1. Male breast cancer is most frequent in elderly patients, but it can occur at any age. The mean age of the onset of the disease is 10 years later in males compared to female patients. Here, the authors review the predisposing factors, main types of male breast cancer, diagnosis and treatment principals. Furthermore, they summarise data of five patients from their practice as regards diagnostic work-up, surgical and adjuvant treatments.