Exploring breast tissue microbial composition and the association with breast cancer risk factors

Antitumor potentials of onco-microbial in Chinese patients with pancreatic cancer

Recent studies have revealed that intratumoral microbiota is implicated in pancreatic cancer (PC), yet the spectra of intratumoral microbiota and their relationship with PC in Chinese patients remained to be clarified. In this study, tumor and paired paracancerous tissue from 53 patients were profiled by bacterial 16S rRNA gene sequencing. Both α- and β-diversity displayed significant differences between tumors and adjacent tissues, with higher diversity in tumors. Three bacteria phyla (Proteobacteria, Firmicutes, and Actinobacteria) were prevalent in both cancers and adjacent normal tissues. A high prevalence of Pseudomonas has been identified in the PC tumor microenvironment and was associated with prolonged overall survival. Furthermore, the results of in vitro experiments suggested that Pseudomonas fluorescens (P. fluorescens) could inhibit the proliferation and induce apoptosis of pancreatic cancer cells. These findings revealed distinctive microbial features of the PC tumors and normal tissues in Chinese populations and exhibited the antitumor potential of P. fluorescens in PC.

Endocrine-targeting therapies shift the breast microbiome to reduce estrogen receptor-α breast cancer risk

Studies indicate that breast tissue has a distinct modifiable microbiome population. We demonstrate that endocrine-targeting therapies, such as tamoxifen, reshape the non-cancerous breast microbiome to influence tissue metabolism and reduce tumorigenesis. Using 16S sequencing, we found that tamoxifen alters β-diversity and increases Firmicutes abundance, including Lactobacillus spp., in mammary glands (MGs) of mice and non-human primates. Immunohistochemistry showed that lipoteichoic acid (LTA)-positive bacteria were elevated in tamoxifen-treated breast tissue. In B6.MMTV-PyMT mice, intra-nipple probiotic bacteria injections reduced tumorigenesis, altered metabolic gene expression, and decreased tumor proliferation. Probiotic-conditioned media selectively reduced viability in estrogen receptor-positive (ER+) breast cancer cells and altered mitochondrial metabolism in non-cancerous epithelial cells. Human tumor samples revealed that LTA-positive bacteria negatively correlated with Ki67, suggesting that endocrine therapies influence tumor-associated microbiota to regulate proliferation. Our data indicate that endocrine-targeting therapies modify the breast microbiome, corresponding with a shift in tissue metabolism to potentially reduce ER+ breast cancer risk.

Metabolites in the Dance: Deciphering Gut-Microbiota-Mediated Metabolic Reprogramming of the Breast Tumor Microenvironment

Breast Cancer (BC) is an important disease causing death of many women worldwide. Here the relationship between gastroenteral microbionta and metabolism in the context of BC is investigated and described in detail. The interrelation between BC, metabolite abnormalities and reprogramming, and micronenvironment is described. All information about the various mechanisms by which these bacterial residents may influence disease initiation, progression, and treatment response is collected and summarized. We will see that gut-based biomarkers, and synergy between conventional therapies and microbiome interventions, together will soon be able to open-up new gates for breast cancer therapy.

Breast cancer (BC), a major cause of death among women worldwide, has traditionally been linked to genetic and environmental factors. However, emerging research highlights the gut microbiome’s significant role in shaping BC development, progression, and treatment outcomes. This review explores the intricate relationship between the gut microbiota and the breast tumor microenvironment, emphasizing how these microbes influence immune responses, inflammation, and metabolic pathways. Certain bacterial species in the gut either contribute to or hinder BC progression by producing metabolites that affect hormone metabolism, immune system pathways, and cellular signaling. An imbalance in gut bacteria, known as dysbiosis, has been associated with a heightened risk of BC, with metabolites like short-chain fatty acids (SCFAs) and enzymes such as β-glucuronidase playing key roles in this process. Additionally, the gut microbiota can impact the effectiveness of chemotherapy, as certain bacteria can degrade drugs like gemcitabine and irinotecan, leading to reduced treatment efficacy. Understanding the complex interactions between gut bacteria and BC may pave the way for innovative treatment approaches, including personalized microbiome-targeted therapies, such as probiotics and fecal microbiota transplants, offering new hope for more effective prevention, diagnosis, and treatment of BC.

Emerging Role of Gut Microbiota in Breast Cancer Development and Its Implications in Treatment

Background: The human digestive system contains approximately 100 trillion bacteria. The gut microbiota is an emerging field of research that is associated with specific biological processes in many diseases, including cardiovascular disease, obesity, diabetes, brain disease, rheumatoid arthritis, and cancer. Emerging evidence indicates that the gut microbiota affects the response to anticancer therapies by modulating the host immune system. Recent studies have explained a high correlation between the gut microbiota and breast cancer: dysbiosis in breast cancer may regulate the systemic inflammatory response, hormone metabolism, immune response, and the tumor microenvironment. Some of the gut bacteria are related to estrogen metabolism, which may increase or decrease the risk of breast cancer by changing the number of hormones. Further, the gut microbiota has been seen to modulate the immune system in respect of its ability to protect against and treat cancers, with a specific focus on hormone receptor-positive breast cancer. Probiotics and other therapies claiming to control the gut microbiome by bacterial means might be useful in the prevention, or even in the treatment, of breast cancer. Conclusions: The present review underlines the various aspects of gut microbiota in breast cancer risk and its clinical application, warranting research on individualized microbiome-modulated therapeutic approaches to breast cancer treatment.

Investigating the role of the intratumoral microbiome in thyroid cancer development and progression

The intratumoral microbiome (ITM) is in the spotlight due to its possible contribution to the initiation, progression, and invasion of a wide range of cancers. Its precise contribution to cancer tumorigenesis is still elusive, though. Thyroid cancer(TC), the ninth leading cause of cancer globally and the most prevalent endocrine malignancy with a rapidly rising incidence among all cancers, has attracted much attention nowadays. Still, the association between the tumor's microbiome and TC progression and development is an evolving area of investigation with significant consequences for disease understanding and intervention. Therefore, this review offers an appropriate perspective on this emerging concept in TC based on prior studies on the ITM among the most common tumors worldwide, concentrating on TC. Moreover, information on the origin of the ITM and practical methods can pave the way for researchers to opt for the most appropriate method for further investigations on the ITM more accurately.

Integrated analysis of microbiota and gut microbial metabolites in blood for breast cancer

Gut microbiota and associated metabolites have been linked to breast carcinogenesis. Evidences demonstrate blood microbiota primarily originates from the gut and may act as a biomarker for breast cancer. We aimed to characterize the microbiota-gut microbial metabolites cross-talk in blood and develop a composite diagnostic panel for breast cancer. We performed 16S rRNA gene sequencing and metabolomics profiling on blood samples from 107 breast cancer cases and 107 age-paired controls. We found that the alpha diversity of the blood microbiota was decreased in breast cancer compared to controls. There were significantly different profiles of microbiota and gut microbial metabolites in blood between these two groups, with nine bacterial genera and four gut microbial metabolites increased in patients, while thirty-nine bacterial genera and two gut microbial metabolites increased in controls. Some breast cancer-associated gut microbial metabolites were linked to differential blood microbiota, and a composite microbiota-metabolite diagnostic panel was further developed with an area under the curve of 0.963 for breast cancer. This study underscored the pivotal role of microbiota and gut microbial metabolites in blood and their interactions for breast carcinogenesis, as well as the potential of a composite diagnostic panel as a non-invasive biomarker for breast cancer.IMPORTANCEOur integrated analysis demonstrated altered profiles of microbiota and gut microbial metabolites in blood for breast cancer patients. The extensive correlation between microbiota and gut microbial metabolites in blood assisted the understanding of the pathogenesis of breast cancer. The good performance of a composite microbiota-gut microbial metabolites panel in blood suggested a non-invasive approach for breast cancer detection and a novel strategy for better diagnosis and prevention of breast cancer in the future.

The Influence of Microbiota on Breast Cancer: A Review

Breast cancer remains one of the leading causes of death among women worldwide, and recent research highlights its growing connection to alterations in the microbiota. This review delves into the intricate relationship between microbiotas and breast cancer, exploring its presence in healthy breast tissue, its changes during cancer progression, and its considerable impact on both the tumor microenvironment (TME) and the tumor immune microenvironment (TIME). We extensively analyze how the microbiota influences cancer growth, invasion, metastasis, resistance to drugs, and the evasion of the immune system, with a special focus on its effects on the TIME. Furthermore, we investigate distinct microbial profiles associated with the four primary molecular subtypes of breast cancer, examining how the microbiota in tumor tissues compares with that in adjacent normal tissues. Emerging studies suggest that microbiotas could serve as valuable diagnostic and prognostic biomarkers, as well as targets for therapy. This review emphasizes the urgent need for further research to improve strategies for breast cancer prevention, diagnosis, and treatment. By offering a detailed examination of the microbiota's critical role in breast cancer, this review aims to foster the development of novel microbiota-based approaches for managing the disease.

Microbiome-Stealth Regulator of Breast Homeostasis and Cancer Metastasis

Cumulative evidence attests to the essential roles of commensal microbes in the physiology of hosts. Although the microbiome has been a major research subject since the time of Luis Pasteur and William Russell over 140 years ago, recent findings that certain intracellular bacteria contribute to the pathophysiology of healthy vs. diseased tissues have brought the field of the microbiome to a new era of investigation. Particularly, in the field of breast cancer research, breast-tumor-resident bacteria are now deemed to be essential players in tumor initiation and progression. This is a resurrection of Russel's bacterial cause of cancer theory, which was in fact abandoned over 100 years ago. This review will introduce some of the recent findings that exemplify the roles of breast-tumor-resident microbes in breast carcinogenesis and metastasis and provide mechanistic explanations for these phenomena. Such information would be able to justify the utility of breast-tumor-resident microbes as biomarkers for disease progression and therapeutic targets.

Nutrition Intervention and Microbiome Modulation in the Management of Breast Cancer

Breast cancer (BC) is one of the most common cancers worldwide and a leading cause of cancer-related deaths among women. The escalating incidence of BC underscores the necessity of multi-level treatment. BC is a complex and heterogeneous disease involving many genetic, lifestyle, and environmental factors. Growing evidence suggests that nutrition intervention is an evolving effective prevention and treatment strategy for BC. In addition, the human microbiota, particularly the gut microbiota, is now widely recognized as a significant player contributing to health or disease status. It is also associated with the risk and development of BC. This review will focus on nutrition intervention in BC, including dietary patterns, bioactive compounds, and nutrients that affect BC prevention and therapeutic responses in both animal and human studies. Additionally, this paper examines the impacts of these nutrition interventions on modulating the composition and functionality of the gut microbiome, highlighting the microbiome-mediated mechanisms in BC. The combination treatment of nutrition factors and microbes is also discussed. Insights from this review paper emphasize the necessity of comprehensive BC management that focuses on the nutrition-microbiome axis.

Postbiotics as Adjuvant Therapy in Cancer Care

Postbiotics are defined as a preparation of inanimate microorganisms and/or their components that confers a health benefit to the host. They range from cell wall fragments to metabolites, bacterial lysates, extracellular vesicles, and short-chain fatty acids (SCFAs). Postbiotics may influence carcinogenesis via a variety of mechanisms. They can promote homeostatic immune responses, reduce inflammation, induce selective cytotoxicity against tumor cells, as well as the enabling the control of tumor cell proliferation and enhancing intestinal epithelial barrier function. Therefore, probiotics can serve as an adjunct strategy in anticancer treatment together with chemotherapy and immunotherapy. Up to now, the only relevant postbiotics used as interventions in oncological patients remain vitamin K molecules, with few phase-II and III trials available. In fact, postbiotics' levels are strictly dependent on the gut microbiota's composition, which may vary between individuals and can be altered under different physiological and pathological conditions. Therefore, the lack of consistent clinical evidence supporting postbiotics' efficacy is due to their poor bioavailability, short half-life, and fluctuating levels. Synbiotics, a mixture of prebiotics and probiotics, are expected to have a more homogeneous bioavailability with respect to postbiotics and may have greater potential for future development. In this review, we focus on the role of postbiotics as an adjuvant therapy in cancer treatment.

Breast Cancer: Extracellular Matrix and Microbiome Interactions

Breast cancer represents the most prevalent form of cancer and the leading cause of cancer-related mortality among females worldwide. It has been reported that several risk factors contribute to the appearance and progression of this disease. Despite the advancements in breast cancer treatment, a significant portion of patients with distant metastases still experiences no cure. The extracellular matrix represents a potential target for enhanced serum biomarkers in breast cancer. Furthermore, extracellular matrix degradation and epithelial-mesenchymal transition constitute the primary stages of local invasion during tumorigenesis. Additionally, the microbiome has a potential influence on diverse physiological processes. It is emerging that microbial dysbiosis is a significant element in the development and progression of various cancers, including breast cancer. Thus, a better understanding of extracellular matrix and microbiome interactions could provide novel alternatives to breast cancer treatment and management. In this review, we summarize the current evidence regarding the intricate relationship between breast cancer with the extracellular matrix and the microbiome. We discuss the arising associations and future perspectives in this field.

Microbial Therapy and Breast Cancer Management: Exploring Mechanisms, Clinical Efficacy, and Integration within the One Health Approach

This comprehensive review elucidates the profound relationship between the human microbiome and breast cancer management. Recent findings highlight the significance of microbial alterations in tissue, such as the gut and the breast, and their role in influencing the breast cancer risk, development, progression, and treatment outcomes. We delve into how the gut microbiome can modulate systemic inflammatory responses and estrogen levels, thereby impacting cancer initiation and therapeutic drug efficacy. Furthermore, we explore the unique microbial diversity within breast tissue, indicating potential imbalances brought about by cancer and highlighting specific microbes as promising therapeutic targets. Emphasizing a holistic One Health approach, this review underscores the importance of integrating insights from human, animal, and environmental health to gain a deeper understanding of the complex microbe-cancer interplay. As the field advances, the strategic manipulation of the microbiome and its metabolites presents innovative prospects for the enhancement of cancer diagnostics and therapeutics. However, rigorous clinical trials remain essential to confirm the potential of microbiota-based interventions in breast cancer management.

The Breast Microbiome in Breast Cancer Risk and Progression: A Narrative Review

A decade ago, studies in human populations first revealed the existence of a unique microbial community in the breast, a tissue historically viewed as sterile, with microbial origins seeded through the nipple and/or translocation from other body sites. Since then, research efforts have been made to characterize the microbiome in healthy and cancerous breast tissues. The purpose of this review is to summarize the current evidence for the association of the breast microbiome with breast cancer risk and progression. Briefly, while many studies have examined the breast microbiome in patients with breast cancer, and compared it with the microbiome of benign breast disease tissue or normal breast tissue, these studies have varied widely in their sample sizes, methods, and quality of evidence. Thus, while several large and rigorous cross-sectional studies have provided key evidence of an altered microbiome in breast tumors compared with normal adjacent and healthy control tissue, there are few consistent patterns of perturbed microbial taxa. In addition, only one large prospective study has provided evidence of a relationship between the breast tumor microbiota and cancer prognosis. Future research studies featuring large, well-characterized cohorts with prospective follow-up for breast cancer incidence, progression, and response to treatment are warranted.

Human Breast Tissue Microbiota Reveals Unique Microbial Signatures that Correlate with Prognostic Features in Adult Ethiopian Women with Breast Cancer

Breast cancer (BC) is the leading cause of cancer mortality among women in Ethiopia. Overall, women of African ancestry have the highest death toll due to BC compared to other racial/ethnic groups. The cause of the disparity in mortality is unclear. Recently, studies conducted in the United States and other high-income countries highlighted the role of microbial dysbiosis in BC initiation, tumor growth, and treatment outcome. However, the extent to which inter-individual differences in the makeup of microbiota are associated with clinical and histopathological outcomes in Ethiopian women has not been studied. The goal of our study was to profile the microbiome in breast tumor and normal adjacent to tumor (NAT) tissues of the same donor and to identify associations between microbial composition and abundance and clinicopathological factors in Ethiopian women with BC. We identified 14 microbiota genera in breast tumor tissues that were distinct from NAT tissues, of which Sphingobium, Anaerococcus, Corynebacterium, Delftia, and Enhydrobacter were most significantly decreased in breast tumors compared to NAT tissues. Several microbial genera significantly differed by clinicopathological factors in Ethiopian women with BC. Specifically, the genus Burkholderia more strongly correlated with aggressive triple negative (TNBC) and basal-like breast tumors. The genera Alkanindiges, Anoxybacillus, Leifsonia, and Exiguobacterium most strongly correlated with HER2-E tumors. Luminal A and luminal B tumors also correlated with Anoxybacillus but not as strongly as HER2-E tumors. A relatively higher abundance of the genus Citrobacter most significantly correlated with advanced-stage breast tumors compared to early-stage tumors. This is the first study to report an association between breast microbial dysbiosis and clinicopathological factors in Ethiopian women.