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

Mechanistic insight and structure activity relationship of isatin-based derivatives in development of anti-breast cancer agents

Breast cancer is most common in women and most difficult to manage that causes highest mortality and morbidity among all diseases and posing significant threat to mankind as well as burden on healthcare system. In 2020, 2.3 million women were diagnosed with breast cancer and it was responsible for 685,000 deaths globally, suggesting the severity of this disease. Apart from that, relapsing of cases and resistance among available anticancer drugs along with associated side effects making the situation even worse. Therefore, it is a global emergency to develop potent and safer antibreast cancer agents. Isatin is most versatile and flying one nucleus which is an integral competent and various anticancer agent in clinical practice and widely used by various research groups around the globe for development of novel, potent, and safer antibreast cancer agents. This review will shed light on the structural insights and antiproliferative potential of various isatin-based derivatives developed for targeting breast cancer in last three decades that will help researchers in design and development of novel, potent, and safer isatin-based antibreast cancer agents.

Non-invasive detection of orthotopic human lung tumors by microRNA expression profiling of mouse exhaled breath condensates and exhaled extracellular vesicles

Aim

The lung is the second most frequent site of metastatic dissemination. Early detection is key to improving survival. Given that the lung interfaces with the external environment, the collection of exhaled breath condensate (EBC) provides the opportunity to obtain biological material including exhaled miRNAs that originate from the lung.

Methods

In this proof-of-principal study, we used the highly metastatic MDA-MB-231 subline 3475 breast cancer cell line (LM-3475) to establish an orthotopic lung tumor-bearing mouse model and investigate non-invasive detection of lung tumors by analysis of exhaled miRNAs. We initially conducted miRNA NGS and qPCR validation analyses on condensates collected from unrestrained animals and identified significant miRNA expression differences between the condensates of lung tumor-bearing and control mice. To focus our purification of EBC and evaluate the origin of these differentially expressed miRNAs, we developed a system to collect EBC directly from the nose and mouth of our mice.

Results

Using nanoparticle distribution analyses, TEM, and ONi super-resolution nanoimaging, we determined that human tumor EVs could be increasingly detected in mouse EBC during the progression of secondary lung tumors. Using our customizable EV-CATCHER assay, we purified human tumor EVs from mouse EBC and demonstrated that the bulk of differentially expressed exhaled miRNAs originate from lung tumors, which could be detected by qPCR within 1 to 2 weeks after tail vein injection of the metastatic cells.

Conclusion

This study is the first of its kind and demonstrates that lung tumor EVs are exhaled in mice and provide non-invasive biomarkers for detection of lung tumors.

Male breast abscess: A rare entity

Breast abscess in males is a rare condition, which accounts for 1%-3% of all documented breast diseases. Males with certain risk factors may develop a breast abscess. The ultrasonographic, mammographic, and pathological characteristics of this case will be highlighted in the report. A 51-year-old morbidly obese Saudi male who is a 160-pack-years smoker presented to our surgical clinic complaining of a right breast mass that presented a long time ago and was changing in size. The mass was painless until 5 days prior to presentation. On physical examination, a firm nonmobile 3 × 4 cm mass was felt at 10-12-o'clock, 1 cm away from the nipple. A bilateral X-ray mammogram and ultrasound were performed with fine needle aspiration and culture. The mammogram of the right breast showed a well-circumscribed subareolar mass with equal density, and it was also associated with overlying skin thickening and relative breast parenchymal edema. The fine needle aspiration grossly showed yellowish-green turbid content followed by turbid blood. The anaerobic culture results showed the gram-positive cocci, Finegoldia Magna. The patient was then instructed to take an antibiotic accordingly and return after 1 week. Fine needle aspiration and culture were performed again after antibiotics and grossly showed 2-3 cc of pus without any growth in culture. Male breast disorders are typically benign, with gynecomastia being the most prevalent, and malignancy being the most serious despite its rarity. Breast abscesses are a challenging clinical condition, and radiologists have a pivotal role in evaluation and follow-up of these lesions.

Prediction models for hormone receptor status in female breast cancer do not extend to males: further evidence of sex-based disparity in breast cancer

Breast cancer prognosis and management for both men and women are reliant upon estrogen receptor alpha (ERα) and progesterone receptor (PR) expression to inform therapy. Previous studies have shown that there are sex-specific binding characteristics of ERα and PR in breast cancer and, counterintuitively, ERα expression is more common in male than female breast cancer. We hypothesized that these differences could have morphological manifestations that are undetectable to human observers but could be elucidated computationally. To investigate this, we trained attention-based multiple instance learning prediction models for ERα and PR using H&E-stained images of female breast cancer from the Cancer Genome Atlas (TCGA) (n = 1085) and deployed them on external female (n = 192) and male breast cancer images (n = 245). Both targets were predicted in the internal (AUROC for ERα prediction: 0.86 ± 0.02, p < 0.001; AUROC for PR prediction = 0.76 ± 0.03, p < 0.001) and external female cohorts (AUROC for ERα prediction: 0.78 ± 0.03, p < 0.001; AUROC for PR prediction = 0.80 ± 0.04, p < 0.001) but not the male cohort (AUROC for ERα prediction: 0.66 ± 0.14, p = 0.43; AUROC for PR prediction = 0.63 ± 0.04, p = 0.05). This suggests that subtle morphological differences invisible upon visual inspection may exist between the sexes, supporting previous immunohistochemical, genomic, and transcriptomic analyses.

Analysis of the distinct features of metastasis male breast cancer and its effect on overall survival based on the SEER database compared with female breast cancer

Background

Male breast cancer (MBC) is a rare disease and differs from female breast cancer (FBC) in clinicopathological and immune tissue types. Given the limited research on MBC due to its rarity, an understanding of the shared and distinct features of MBC and FBC is vital for formulating efficacious treatment strategies.

Methods

Data of patients diagnosed with metastatic breast cancer in the Surveillance, Epidemiology, and End Results (SEER) database from 2012 to 2017 were analysed. Chi-square test was used to compare clinicopathological characteristics between male and female patients. Kaplan-Meier analysis was utilized to compare differences in overall survival (OS).

Results

A total of 2,858 patients with MBC were studied, 134 of whom had distant metastasis. Compared with 8,698 patients with metastatic FBC, a higher proportion of metastatic MBC patients had tumors located in the center of the breast, received surgical treatment, and had bone + lung metastasis. Survival analysis revealed no difference in OS between metastatic MBC and FBC patients (P=0.27), but there was a significant difference in OS between metastatic and nonmetastatic MBC (P=0.004). Compared with metastatic FBC, MBC patients with bone metastasis alone, lung metastasis alone, liver metastasis alone, and bone + lung metastasis also had worse prognosis (P=0.021, 0.019, 0.024, 0.011, respectively).

Conclusions

Metastatic MBC has unique clinicopathological disease features and patterns of metastasis. No significant difference between the survival of metastatic MBC and FBC patients was observed. Distant metastasis was an independent risk factor impacting the prognosis of MBC patients.

Non-retroareolar male mucinous breast cancer without gynecomastia development in an elderly man: A case report

BACKGROUND

Male breast cancer (MBC) is an extremely rare condition and accounts for less than 1% of all breast cancers, and malignant tumors occur in less than 1% of the affected men. Mucinous breast cancer is extremely rare and accounts for 2% of all invasive breast cancers. Generally, MBC is accompanied by a retroareolar mass.

CASE SUMMARY

Herein, we report a case of male mucinous breast carcinoma (MMBC) without gynecomastia development and with mass localization outside the common retroareolar region, wherein the mass was a painless nodule in the right breast of a 64-year-old man. We also discuss the clinical and pathological characteristics of this unusual tumor. The excised breast specimen showed pure mucinous carcinoma. The patient had strong expression of estrogen and progesterone receptors, a low Ki-67 proliferation index of the tumor cells, and negative pathological axillary lymph nodes. The patient underwent modified radical mastectomy and axillary lymph node dissection, followed by tamoxifen hormone therapy.

CONCLUSION

To the best of our knowledge, this is the first case report of MMBC in the non-retroareolar region of the nipple without gynecomastia development. Mucinous tumors are easily missed during diagnosis, and the incidence of axillary lymph node metastases of chest mucinous tumors has increased.

Male breast cancer: Report of two cases with bloody nipple discharge

We report 2 rare cases of male breast cancer with bloody nipple discharge. Patient 1, a 32-year-old male, presented with a bloody nipple discharge from the left breast. Diagnostic workup revealed papillary ductal carcinoma in situ. Patient 1 underwent bilateral mastectomy with left axillary sentinel lymph node biopsy and has been doing well ever since. Patient 2, a 70-year-old male with concomitant metastatic prostate cancer, presented with a palpable right breast mass and with initially serous, then bloody nipple discharge. Diagnostic workup revealed invasive ductal carcinoma with ductal carcinoma in situ of the right breast. Patient 2 received aromatase inhibitor therapy prior to right total mastectomy with SLN biopsy followed by adjuvant tamoxifen therapy. Patient 2 recovered without complication for 2 years until metastatic disease recurrence was detected. This case report's purpose is to increase awareness and enhance understanding of the presentation, diagnosis, treatment, and outcomes of rare malignant pathologies.

Proteomics-Based Identification of Dysregulated Proteins and Biomarker Discovery in Invasive Ductal Carcinoma, the Most Common Breast Cancer Subtype

Invasive ductal carcinoma (IDC) is the most common histological subtype of malignant breast cancer (BC), and accounts for 70–80% of all invasive BCs. IDC demonstrates great heterogeneity in clinical and histopathological characteristics, prognoses, treatment strategies, gene expressions, and proteomic profiles. Significant proteomic determinants of the progression from intraductal pre-invasive malignant lesions of the breast, which characterize a ductal carcinoma in situ (DCIS), to IDC, are still poorly identified, validated, and clinically applied. In the era of “6P” medicine, it remains a great challenge to determine which patients should be over-treated versus which need to be actively monitored without aggressive treatment. The major difficulties for designating DCIS to IDC progression may be solved by understanding the integrated genomic, transcriptomic, and proteomic bases of invasion. In this review, we showed that multiple proteomics-based techniques, such as LC–MS/MS, MALDI-ToF MS, SELDI-ToF-MS, MALDI-ToF/ToF MS, MALDI-MSI or MasSpec Pen, applied to in-tissue, off-tissue, BC cell lines and liquid biopsies, improve the diagnosis of IDC, as well as its prognosis and treatment monitoring. Classic proteomics strategies that allow the identification of dysregulated protein expressions, biological processes, and interrelated pathway analyses based on aberrant protein–protein interaction (PPI) networks have been improved to perform non-invasive/minimally invasive biomarker detection of early-stage IDC. Thus, in modern surgical oncology, highly sensitive, rapid, and accurate MS-based detection has been coupled with “proteome point sampling” methods that allow for proteomic profiling by in vivo “proteome point characterization”, or by minimal tissue removal, for ex vivo accurate differentiation and delimitation of IDC. For the detection of low-molecular-weight proteins and protein fragments in bodily fluids, LC–MS/MS and MALDI-MS techniques may be coupled to enrich and capture methods which allow for the identification of early-stage IDC protein biomarkers that were previously invisible for MS-based techniques. Moreover, the detection and characterization of protein isoforms, including posttranslational modifications of proteins (PTMs), is also essential to emphasize specific molecular mechanisms, and to assure the early-stage detection of IDC of the breast.

A Prospective Population-Based Study of Cardiovascular Disease Mortality following Treatment for Breast Cancer among Men in the United States, 2000-2019

Male breast cancer is rare but its incidence and mortality are increasing in the United States, with racial/ethnic disparities in survival reported. There is limited evidence for cardiotoxicity of cancer treatment among men with breast cancer. We evaluated the relation between breast cancer treatment and cardiovascular disease (CVD) mortality among men and investigated the salient roles that race/ethnicity play on this relation. Data were from 5216 men with breast cancer aged ≥ 40 years from the Surveillance, Epidemiology, and End Results program who were diagnosed from 2000 to 2019 and underwent surgery. Competing risk models were used to estimate hazards ratios (HR) and 95% confidence intervals (CI). During a median follow-up of 5.6 years, 1914 deaths occurred with 25% attributable to CVD. In multivariable-adjusted models, men who received chemotherapy had elevated risk for CVD (HR: 1.55, 95%CI: 1.18-2.04). This risk was higher among Hispanic men (HR: 3.96, 95%CI: 1.31-12.02) than non-Hispanic Black and non-Hispanic White men. There was no significant association between radiotherapy and CVD deaths. In this population-based study, treatment with chemotherapy was associated with elevated risk of CVD mortality in men with breast cancer. Racial/ethnic disparities in the association of chemotherapy and CVD mortality were observed.

CDH1 (E-cadherin) Gene Methylation in Human Breast Cancer: Critical Appraisal of a Long and Twisted Story

Simple Summary

Genes can be inactivated by specific modifications of DNA bases, most often by adding a methyl group to the DNA base cytosine if it is followed by guanosine (CG methylation). This modification prevents gene expression and has been reported for many different genes in nearly all types of cancer. A prominent example is the gene CDH1, which encodes the cell-adhesion molecule E-cadherin. This is an important player in the spreading of tumor cells within the body (metastasis). Particularly in human breast cancer, many different research groups have studied the inactivation of the CDH1 gene via DNA methylation using various methods. Over the last 20 years, different, in part, even contradicting results have been published for the CDH1 gene in breast cancer. This review summarizes the most important publications and explains the bewildering heterogeneity of results through careful analysis of the methods which have been used.

Abstract

Epigenetic inactivation of a tumor suppressor gene by aberrant DNA methylation is a well-established defect in human tumor cells, complementing genetic inactivation by mutation (germline or somatic). In human breast cancer, aberrant gene methylation has diagnostic, prognostic, and predictive potential. A prominent example is the hypermethylation of the CDH1 gene, encoding the adhesion protein E-Cadherin (“epithelial cadherin”). In numerous publications, it is reported as frequently affected by gene methylation in human breast cancer. However, over more than two decades of research, contradictory results concerning CDH1 gene methylation in human breast cancer accumulated. Therefore, we review the available evidence for and against the role of DNA methylation of the CDH1 gene in human breast cancer and discuss in detail the methodological reasons for conflicting results, which are of general importance for the analysis of aberrant DNA methylation in human cancer specimens. Since the loss of E-cadherin protein expression is a hallmark of invasive lobular breast cancer (ILBC), special attention is paid to CDH1 gene methylation as a potential mechanism for loss of expression in this special subtype of human breast cancer. Proper understanding of the methodological basis is of utmost importance for the correct interpretation of results supposed to demonstrate the presence and clinical relevance of aberrant DNA methylation in cancer specimens.

Prevalence of Cancer Predisposition Germline Variants in Male Breast Cancer Patients: Results of the German Consortium for Hereditary Breast and Ovarian Cancer

Male breast cancer (mBC) is associated with a high prevalence of pathogenic variants (PVs) in the BRCA2 gene; however, data regarding other BC predisposition genes are limited. In this retrospective multicenter study, we investigated the prevalence of PVs in BRCA1/2 and 23 non-BRCA1/2 genes using a sample of 614 patients with mBC, recruited through the centers of the German Consortium for Hereditary Breast and Ovarian Cancer. A high proportion of patients with mBC carried PVs in BRCA2 (23.0%, 142/614) and BRCA1 (4.6%, 28/614). The prevalence of BRCA1/2 PVs was 11.0% in patients with mBC without a family history of breast and/or ovarian cancer. Patients with BRCA1/2 PVs did not show an earlier disease onset than those without. The predominant clinical presentation of tumor phenotypes was estrogen receptor (ER)-positive, progesterone receptor (PR)-positive, and HER2-negative (77.7%); further, 10.2% of the tumors were triple-positive, and 1.2% were triple-negative. No association was found between ER/PR/HER2 status and BRCA1/2 PV occurrence. Comparing the prevalence of protein-truncating variants (PTVs) between patients with mBC and control data (ExAC, n = 27,173) revealed significant associations of PTVs in both BRCA1 and BRCA2 with mBC (BRCA1: OR = 17.04, 95% CI = 10.54−26.82, p < 10−5; BRCA2: OR = 77.71, 95% CI = 58.71−102.33, p < 10−5). A case-control investigation of 23 non-BRCA1/2 genes in 340 BRCA1/2-negative patients and ExAC controls revealed significant associations of PTVs in CHEK2, PALB2, and ATM with mBC (CHEK2: OR = 3.78, 95% CI = 1.59−7.71, p = 0.002; PALB2: OR = 14.77, 95% CI = 5.02−36.02, p < 10−5; ATM: OR = 3.36, 95% CI = 0.89−8.96, p = 0.04). Overall, our findings support the benefit of multi-gene panel testing in patients with mBC irrespective of their family history, age at disease onset, and tumor phenotype.