Microbial dysbiosis is associated with human breast cancer

Drug Metabolism for the Identification of Clinical Biomarkers in Breast Cancer

Breast cancer is classified into four major molecular subtypes, and is considered a heterogenous disease. The risk profiles and treatment of breast cancer differ according to these subtypes. Early detection dramatically improves the prospects of successful treatment, resulting in a reduction in overall mortality rates. However, almost 30% of women primarily diagnosed with the early-stage disease will eventually develop metastasis or resistance to chemotherapies. Immunotherapies are among the most promising cancer treatment options; however, long-term clinical benefit has only been observed in a small subset of responding patients. The current strategies for diagnosis and treatment rely heavily on histopathological examination and molecular diagnosis, disregarding the tumor microenvironment and microbiome involving cancer cells. In this review, we aim to praise the use of pharmacogenomics and pharmacomicrobiomics as a strategy to identify potential biomarkers for guiding and monitoring therapy in real-time. The finding of these biomarkers can be performed by studying the metabolism of drugs, more specifically, immunometabolism, and its relationship with the microbiome, without neglecting the information provided by genetics. A larger understanding of cancer biology has the potential to improve patient care, enable clinical decisions, and deliver personalized medicine.

Regulation of tissue-resident memory T cells by the Microbiota

Resident memory T cells (Trms) predominantly reside within tissue and are critical for providing rapid protection against invasive viruses, fungi and bacteria. Given that tissues are heavily impacted and shaped by the microbiota, it stands to reason that Trms are also influenced by the microbiota that inhabits barrier sites. The influence of the microbiota is largely mediated by microbial production of metabolites which are crucial to the immune response to both viral infection and cancerous tumors. In addition to the effects of metabolites, antigens derived from the microbiota can activate T cell responses. While microbiota-specific T cells may assist in tissue repair, control of infection and anti-tumor immunity, the actual 'memory' potential of these cells remains unclear. Here, we hypothesize that memory responses to antigens from the microbiota must be 'licensed' by inflammatory signals activated by invasion of the host by microorganisms.

Role of Microbiota-Gut-Brain Axis in Regulating Dopaminergic Signaling

Dopamine is a neurotransmitter that plays a critical role both peripherally and centrally in vital functions such as cognition, reward, satiety, voluntary motor movements, pleasure, and motivation. Optimal dopamine bioavailability is essential for normal brain functioning and protection against the development of neurological diseases. Emerging evidence shows that gut microbiota have significant roles in maintaining adequate concentrations of dopamine via intricate, bidirectional communication known as the microbiota-gut-brain axis. The vagus nerve, immune system, hypothalamus–pituitary–adrenal axis, and microbial metabolites serve as important mediators of the reciprocal microbiota-gut-brain signaling. Furthermore, gut microbiota contain intrinsic enzymatic activity that is highly involved in dopamine metabolism, facilitating dopamine synthesis as well as its metabolite breakdown. This review examines the relationship between key genera of gut microbiota such as Prevotella, Bacteroides, Lactobacillus, Bifidobacterium, Clostridium, Enterococcus, and Ruminococcus and their effects on dopamine. The effects of gut dysbiosis on dopamine bioavailability and the subsequent impact on dopamine-related pathological conditions such as Parkinson’s disease are also discussed. Understanding the role of gut microbiota in modulating dopamine activity and bioavailability both in the periphery and in the central nervous system can help identify new therapeutic targets as well as optimize available methods to prevent, delay, or restore dopaminergic deficits in neurologic and metabolic disorders.

Microbiota and cancer: current understanding and mechanistic implications

During last few decades, role of microbiota and its importance in several diseases has been a hot topic for research. The microbiota is considered as an accessory organ for maintaining normal physiology of an individual. These microbiota organisms which normally colonize several epithelial surfaces are known to secrete several small molecules leading to local and systemic effects on normal biological processes. The role of microbiota is also established in carcinogenesis as per several recent findings. The effects of microbiota on cancer is not only limited to their contribution in oncogenesis, but the overall susceptibility for oncogenesis and its subsequent progression, development of coinfections, and response to anticancer therapy is also found to be affected by microbiota. The information about microbiota and subsequent contributions of microbes in anticancer response motivated researchers in development of microbes-based anticancer therapeutics. We provided current status of microbiota contribution in oncogenesis with special reference to their mechanistic implications in different aspects of oncogenesis. In addition, the mechanistic implications of bacteria in anticancer therapy are also discussed. We conclude that several mechanisms of microbiota-mediated regulation of oncogenesis is known, but approaches must be focused on understanding contribution of microbiota as a community rather than single organisms-mediated effects.

Microbiome composition indicate dysbiosis and lower richness in tumor breast tissues compared to healthy adjacent paired tissue, within the same women

Background

Breast cancer (BC) is the most common malignancy in women, in whom it reaches 20% of the total neoplasia incidence. Most BCs are considered sporadic and a number of factors, including familiarity, age, hormonal cycles and diet, have been reported to be BC risk factors. Also the gut microbiota plays a role in breast cancer development. In fact, its imbalance has been associated to various human diseases including cancer although a consequential cause-effect phenomenon has never been proven.

Methods

The aim of this work was to characterize the breast tissue microbiome in 34 women affected by BC using an NGS-based method, and analyzing the tumoral and the adjacent non-tumoral tissue of each patient.

Results

The healthy and tumor tissues differed in bacterial composition and richness: the number of Amplicon Sequence Variants (ASVs) was higher in healthy tissues than in tumor tissues (p = 0.001). Moreover, our analyses, able to investigate from phylum down to species taxa for each sample, revealed major differences in the two richest phyla, namely, Proteobacteria and Actinobacteria. Notably, the levels of Actinobacteria and Proteobacteria were, respectively, higher and lower in healthy with respect to tumor tissues.

Conclusions

Our study provides information about the breast tissue microbial composition, as compared with very closely adjacent healthy tissue (paired samples within the same woman); the differences found are such to have possible diagnostic and therapeutic implications; further studies are necessary to clarify if the differences found in the breast tissue microbiome are simply an association or a concausative pathogenetic effect in BC. A comparison of different results on similar studies seems not to assess a universal microbiome signature, but single ones depending on the environmental cohorts’ locations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09074-y.

Salivary Microbiome in Adenoid Cystic Carcinoma Detected by 16S rRNA Sequencing and Shotgun Metagenomics

Microorganisms are confirmed to be closely related to the occurrence and development of cancers in human beings. However, there has been no published report detailing relationships between the oral microbiota and salivary adenoid cystic carcinoma (SACC). In this study, unstimulated saliva was collected from 13 SACC patients and 10 healthy controls. The microbial diversities, compositions and functions were comprehensively analyzed after 16S rRNA sequencing and whole-genome shotgun metagenomic sequencing. The alpha diversity showed no significant difference between SACC patients and healthy controls, while beta diversity showed a separation trend. The SACC patients showed higher abundances of Streptococcus and Rothia, while Prevotella and Alloprevotella were more abundant in healthy controls. The prevalent KEGG pathways, carbohydrate-active enzymes, antibiotic resistances and virulence factors as well as the biomarkers in SACC were determined by functional gene analysis. Our study preliminarily investigated the salivary microbiome of SACC patients compared with healthy controls and might be the basis for further studies on novel diagnostic and treatment strategies.

Alterations of the Oral Microbiota Profiles in Chinese Patient With Oral Cancer

Oral cancer is the most common malignant tumor in the oral and maxillofacial region, of which more than 90% is squamous cell carcinoma. The incidence of oral cancer is on the rise worldwide. An imbalance between the microorganism composition and its host may lead to the occurrence of oral malignant tumors. Accumulating evidence suggests that the oral microbiota plays an important role in oral cancer; however, the association between oral microbiota and oral cancer has not yet been comprehensively studied. In this study, metagenomic sequencing was used to compare the microbial composition of three groups of samples from Chinese patients with oral cancer, patients with precancerous lesion, and normal individuals. In terms of microbiota richness, the oral microbiota of patients with precancerous lesions was richer than that of oral cancer patients and healthy controls, whereas in terms of microbiota diversity, there was little difference between the three groups. The three groups of samples exhibited statistically significant differences in microbiota composition and metabolic function at the family, genus, and species levels (P < 0.05). The differentially enriched phylum in oral cancer samples was Bacteroidetes (P < 0.05). At the genus level, the main differentially enriched taxa were Prevotella, Peptostreptococcus, Carnobacterium, and Diastella (P < 0.05). The species level was differentially enriched in Prevotella intermedia and Peptostreptococcus stomatis (p < 0.05). The prediction of microbiota function shows that oral cancer is mainly associated with coenzyme A biosynthesis, phosphopantothenic acid biosynthesis, inosine 5’-phosphate degradation, and riboflavin biosynthesis. Furthermore, the increase in C-reactive protein level in oral cancer patients was found to be closely related to P. intermedia. Overall, oral bacterial profiles showed significant differences between the oral cancer group and normal group. Hence, microbes can be employed as diagnostic markers and treatment targets for oral cancer.

Microbiota of Breast Tissue and Its Potential Association with Regional Recurrence of Breast Cancer in Korean Women

Recent studies have reported dysbiosis of the microbiome in breast tissue collected from patients with breast cancer and the association between the microbiota and disease progression. However, the role of the microbiota in breast tissue remains unclear, possibly due to the complexity of breast cancer and various factors, including racial and geographical differences, influencing microbiota in breast tissue. Here, to determine the potential role of microbiota in breast tumor tissue, we analyzed 141 tissue samples based on three different tissue types (tumor, adjacent normal, and lymph node tissues) from the same patients with breast cancer in Korea. The microbiota was not simply distinguishable based on tissue types. However, the microbiota could be divided into two cluster types, even within the same tissue type, and the clinicopathologic factors were differently correlated in the two cluster types. Risk of regional recurrence was also significantly different between the microbiota cluster types (p = 0.014). In predicted function analysis, the pentose and glucuronate interconversions were significantly different between the cluster types (q < 0.001), and Enterococcus was the main genus contributing to these differences (q < 0.01). Results showed that the microbiota of breast tissue could interact with the host and influence the risk of regional recurrence. Although further studies would be recommended to validate our results, this study could expand our understanding on the breast tissue microbiota, and the results might be applied to develop novel prediction methods and treatments for patients with breast cancer.

The involvement of oncobiosis and bacterial metabolite signaling in metastasis formation in breast cancer

Breast cancer, the most frequent cancer in women, is characterized by pathological changes to the microbiome of breast tissue, the tumor, the gut, and the urinary tract. Changes to the microbiome are determined by the stage, grade, origin (NST/lobular), and receptor status of the tumor. This year is the 50th anniversary of when Hill and colleagues first showed that changes to the gut microbiome can support breast cancer growth, namely that the oncobiome can reactivate excreted estrogens. The currently available human and murine data suggest that oncobiosis is not a cause of breast cancer, but can support its growth. Furthermore, preexisting dysbiosis and the predisposition to cancer are transplantable. The breast's and breast cancer's inherent microbiome and the gut microbiome promote breast cancer growth by reactivating estrogens, rearranging cancer cell metabolism, bringing about a more inflammatory microenvironment, and reducing the number of tumor-infiltrating lymphocytes. Furthermore, the gut microbiome can produce cytostatic metabolites, the production of which decreases or blunts breast cancer. The role of oncobiosis in the urinary tract is largely uncharted. Oncobiosis in breast cancer supports invasion, metastasis, and recurrence by supporting cellular movement, epithelial-to-mesenchymal transition, cancer stem cell function, and diapedesis. Finally, the oncobiome can modify the pharmacokinetics of chemotherapeutic drugs. The microbiome provides novel leverage on breast cancer that should be exploited for better management of the disease.

The intratumoral microbiome: Characterization methods and functional impact

Live-pathogenic bacteria, which were identified inside tumors hundreds year ago, are key elements in modern cancer research. As they have a relatively accessible genome, they offer a multitude of metabolic engineering opportunities, useful in several clinical fields. Better understanding of the tumor microenvironment and its associated microbiome would help conceptualize new metabolically engineered species, triggering efficient therapeutic responses against cancer. Unfortunately, given the low microbial biomass nature of tumors, characterizing the tumor microbiome remains a challenge. Tumors have a high host versus bacterial DNA ratio, making it extremely complex to identify tumor-associated bacteria. Nevertheless, with the improvements in next-generation analytic tools, recent studies demonstrated the existence of intratumor bacteria inside defined tumors. It is now proven that each cancer subtype has a unique microbiome, characterized by bacterial communities with specific metabolic functions. This review provides a brief overview of the main approaches used to characterize the tumor microbiome, and of the recently proposed functions of intracellular bacteria identified in oncological entities. The therapeutic aspects of live-pathogenic microbes are also discussed, regarding the tumor microenvironment of each cancer type.

The role played by bacterial infections in the onset and metastasis of cancer

Understanding various responses of cells towards change in their external environment, presence of other species and is important in identifying and correlating the mechanisms leading to malignant transformations and cancer development. Although uncovering and comprehending the association between bacteria and cancer is highly challenging, it promises excellent perspectives and approaches for successful cancer therapy. This review introduces various bacterial species, their virulence factors, and their role in cell transformations leading to cancer (particularly gastric, oral, colon, and breast cancer). Bacterial dysbiosis permutates host cells, causes inflammation, and results in tumorigenesis. This review explored bacterial-mediated host cell transformation causing chronic inflammation, immune receptor hyperactivation/absconding immune recognition, and genomic instability. Bacterial infections downregulate E-cadherin, leading to loosening of epithelial tight junction polarity and triggers metastasis. In addition to understanding the role of bacterial infections in cancer development, we have also reviewed the application of bacteria for cancer therapy. The emergence of bacteriotherapy combined with conventional therapies led to new and effective ways of overcoming challenges associated with available treatments. This review discusses the application of bacterial minicells, microswimmers, and outer cell membrane vesicles (OMV) for drug delivery applications.

Cáncer y Microbiota

El cuerpo humano está expuesto continuamente a microorganismos tanto fijos como transitorios, así como sus metabolitos tóxicos, lo cual puede conducir a la aparición y progresión del cáncer en sitios distantes al hábitat particular de cada microbio. Diversos estudios científicos han hecho posible entender la relación estrecha que existe entre microbioma y cáncer, ya que los componentes del primero, al tener la capacidad de migrar a diferentes zonas del cuerpo, pueden contribuir al desarrollo de diversas enfermedades crónicas. Los estudios de metagenómica sugieren que la disbiosis, en la microbiota comensal, está asociada con trastornos inflamatorios y varios tipos de cáncer, los cuales pueden ocurrir por sus efectos sobre el metabolismo, la proliferación celular y la inmunidad. La microbiota puede producir el cáncer cuando existen condiciones predisponentes, como en la etapa inicial de la progresión tumoral (iniciación), inestabilidad genética, susceptibilidad a la respuesta inmune del huésped, a la progresión y la respuesta a la terapia. La relación más estrecha, entre el microbioma y el cáncer, es a través de la desregulación del sistema inmune. En este trabajo revisamos las actuales evidencias sobre la asociación entre la microbiota y algunos tipos de cáncer como el cáncer gástrico, colorrectal, próstata, ovario, oral, pulmón y mama.

Current Knowledge About the Implication of Bacterial Microbiota in Human Health and Disease

Recent advances in molecular genetics and the invention of new technologies led to a development in our knowledge about human microbiota, specifically bacterial one. The microbiota plays a fundamental role in the immunologic, hormonal and metabolic homeostasis of the host. After the initiation of the Human Microbiome Project, it became clear that the human microbiota consists of the 10-100 trillion symbiotic microbial cells harbored by each person, primarily bacteria in the gut, but also in other spots as the skin, mouth, nose, and vagina. Despite of the differences in studying bacterial species, decreased bacterial diversity and persistence has been connected with several diverse human diseases primarily diabetes, IBD (inflammatory bowel disease) and others; attempts were made even to explain psychiatric pathology. Several species emerged as dominant and were clearly linked to certain disorders or accepted as biomarkers of others. The current review aims to discuss key issues of our current knowledge about bacteria in human, the difficulties and methods of its analysis, its contribution to human health and responsibility for human diseases.

Metabolomics-Microbiome Crosstalk in the Breast Cancer Microenvironment

Breast cancer, the most frequent cancer diagnosed among females, is associated with a high mortality rate worldwide. Alterations in the microbiota have been linked with breast cancer development, suggesting the possibility of discovering disease biomarkers. Metabolomics has emerged as an advanced promising analytical approach for profiling metabolic features associated with breast cancer subtypes, disease progression, and response to treatment. The microenvironment compromises non-cancerous cells such as fibroblasts and influences cancer progression with apparent phenotypes. This review discusses the role of metabolomics in studying metabolic dysregulation in breast cancer caused by the effect of the tumor microenvironment on multiple cells such as immune cells, fibroblasts, adipocytes, etc. Breast tumor cells have a unique metabolic profile through the elevation of glycolysis and the tricarboxylic acid cycle metabolism. This metabolic profile is highly sensitive to microbiota activity in the breast tissue microenvironment. Metabolomics shows great potential as a tool for monitoring metabolic dysregulation in tissue and associating the findings with microbiome expression.

Spot-light on microbiota in obesity and cancer

Over the last few years, the complexity and diversity of gut microbiota within and across individuals has been detailed in relation to human health. Further, understanding of the bidirectional association between gut microbiota and metabolic disorders has highlighted a complimentary, yet crucial role for microbiota in the onset and progression of obesity-related cancers. While strategies for cancer prevention and cure are known to work efficiently when supported by healthy diet and lifestyle choices and physical activity, emerging evidence suggests that the complex interplay relating microbiota both to neoplastic and metabolic diseases could aid strategies for cancer treatment and outcomes. This review will explore the experimental and clinical grounds supporting the functional role of gut microbiota in the pathophysiology and progression of cancers in relation to obesity and its metabolic correlates. Therapeutic approaches aiding microbiota restoration in connection with cancer treatments will be discussed.

Interaction between intestinal microbiota and tumour immunity in the tumour microenvironment

In recent years, an increasing number of studies have reported that intestinal microbiota have an important effect on tumour immunity by affecting the tumour microenvironment (TME). The intestinal microbiota are closely associated with various immune cells, such as T lymphocytes, natural killer cells (NK cells) and macrophages. Some bacteria, such as Akkermansia muciniphila (A. muciniphila) and Lactobacillus reuteri (L. reuteri), have been shown to improve the effect of tumour immunity. Furthermore, microbial imbalance, such as the increased abundance of Fusobacterium nucleatum (F. nucleatum) and Helicobacter hepaticus (H. hepaticus), generally causes tumour formation and progression. In addition, some microbiota also play important roles in tumour immunotherapy, especially PD-L1-related therapies. Therefore, what is the relationship between these processes and how do they affect each other? In this review, we summarize the interactions and corresponding mechanisms among the intestinal microbiota, immune system and TME to facilitate the research and development of new targeted drugs and provide new approaches to tumour therapy.

Short- and Long-Term Implications of Human Milk Microbiota on Maternal and Child Health

Human milk (HM) is considered the most complete food for infants as its nutritional composition is specifically designed to meet infant nutritional requirements during early life. HM also provides numerous biologically active components, such as polyunsaturated fatty acids, milk fat globules, IgA, gangliosides or polyamines, among others; in addition, HM has a “bifidogenic effect”, a prebiotic effect, as a result of the low concentration of proteins and phosphates, as well as the presence of lactoferrin, lactose, nucleotides and oligosaccharides. Recently, has been a growing interest in HM as a potential source of probiotics and commensal bacteria to the infant gut, which might, in turn, influence both the gut colonization and maturation of infant immune system. Our review aims to address practical approaches to the detection of microbial communities in human breast milk samples, delving into their origin, composition and functions. Furthermore, we will summarize the current knowledge of how HM microbiota dysbiosis acts as a short- and long-term predictor of maternal and infant health. Finally, we also provide a critical view of the role of breast milk-related bacteria as a novel probiotic strategy in the prevention and treatment of maternal and offspring diseases.

Characterizing the breast cancer lipidome and its interaction with the tissue microbiota

Breast cancer is the most diagnosed cancer amongst women worldwide. We have previously shown that there is a breast microbiota which differs between women who have breast cancer and those who are disease-free. To better understand the local biochemical perturbations occurring with disease and the potential contribution of the breast microbiome, lipid profiling was performed on non-tumor breast tissue collected from 19 healthy women and 42 with breast cancer. Here we identified unique lipid signatures between the two groups with greater amounts of lysophosphatidylcholines and oxidized cholesteryl esters in the tissue from women with breast cancer and lower amounts of ceramides, diacylglycerols, phosphatidylcholines, and phosphatidylethanolamines. By integrating these lipid signatures with the breast bacterial profiles, we observed that Gammaproteobacteria and those from the class Bacillus, were negatively correlated with ceramides, lipids with antiproliferative properties. In the healthy tissues, diacylglyerols were positively associated with Acinetobacter, Lactococcus, Corynebacterium, Prevotella and Streptococcus. These bacterial groups were found to possess the genetic potential to synthesize these lipids. The cause-effect relationships of these observations and their contribution to disease patho-mechanisms warrants further investigation for a disease afflicting millions of women around the world.

Biomarkers of immunotherapy response in breast cancer beyond PD-L1

Immune checkpoint inhibitors have modified the treatment algorithm in a variety of cancer types, including breast cancer. Nevertheless, optimal selection of ideal candidates to these drugs remains an unmet need. Although PD-L1 expression by immunohistochemistry seems to be the most promising biomarker to date, its predictive ability is far from ideal. Thus, the development of new predictive biomarkers is essential for a better selection of patients. Here, we discuss potential biomarkers beyond PD-L1 that could play an important role in precision cancer immunotherapy.

The role of the tumor microbe microenvironment in the tumor immune microenvironment: bystander, activator, or inhibitor?

The efficacy of cancer immunotherapy largely depends on the tumor microenvironment, especially the tumor immune microenvironment. Emerging studies have claimed that microbes reside within tumor cells and immune cells, suggesting that these microbes can impact the state of the tumor immune microenvironment. For the first time, this review delineates the landscape of intra-tumoral microbes and their products, herein defined as the tumor microbe microenvironment. The role of the tumor microbe microenvironment in the tumor immune microenvironment is multifaceted: either as an immune activator, inhibitor, or bystander. The underlying mechanisms include: (I) the presentation of microbial antigens by cancer cells and immune cells, (II) microbial antigens mimicry shared with tumor antigens, (III) microbe-induced immunogenic cell death, (IV) microbial adjuvanticity mediated by pattern recognition receptors, (V) microbe-derived metabolites, and (VI) microbial stimulation of inhibitory checkpoints. The review further suggests the use of potential modulation strategies of the tumor microbe microenvironment to enhance the efficacy and reduce the adverse effects of checkpoint inhibitors. Lastly, the review highlights some critical questions awaiting to be answered in this field and provides possible solutions. Overall, the tumor microbe microenvironment modulates the tumor immune microenvironment, making it a potential target for improving immunotherapy. It is a novel field facing major challenges and deserves further exploration.

Microbiome and cancer

The human microbiome constitutes a complex multikingdom community that symbiotically interacts with the host across multiple body sites. Host-microbiome interactions impact multiple physiological processes and a variety of multifactorial disease conditions. In the past decade, microbiome communities have been suggested to influence the development, progression, metastasis formation, and treatment response of multiple cancer types. While causal evidence of microbial impacts on cancer biology is only beginning to be unraveled, enhanced molecular understanding of such cancer-modulating interactions and impacts on cancer treatment are considered of major scientific importance and clinical relevance. In this review, we describe the molecular pathogenic mechanisms shared throughout microbial niches that contribute to the initiation and progression of cancer. We highlight advances, limitations, challenges, and prospects in understanding how the microbiome may causally impact cancer and its treatment responsiveness, and how microorganisms or their secreted bioactive metabolites may be potentially harnessed and targeted as precision cancer therapeutics.

Effect of Microbiota in the Development of Breast Cancer

Breast cancer is the most frequent cancer among women and causes the greatest number of cancer-related death among women all over the world. It approximately accounts for 15% of all cancer death. The human microbiota is the term applied to the aggregate of microbes that live in different habitats of living organisms 'bodies, including the gut, skin, vagina, and mouth, as well as nose, conjunctiva, pharynx, and urethra, among others. Increasing evidence is pointing to the role of the microbiome in the occurrence and development of a variety of cancers. Intestinal microbiome imbalance is related to the occurrence of gastrointestinal tumors, such as esophageal, gastric, colorectal, and gallbladder cancer. The present study aimed to identify the role of microbiota in the development of breast cancer. The women with breast cancer (n=130) in this study were in the age range of 25-75 years. The study was conducted in Kirkuk city of Iraq from September 10, 2019, to March 15, 2020. The control group included 20 women diagnosed with benign breast lesions in the age range 25-75 years, who matched the women in the patient group. Blood samples and breast tissue samples were taken from patients with breast cancer and benign breast lesions. Blood samples were examined through immunological methods, enzyme-linked immunosorbent assay (ELISA) was adopted for the detection of interleukin-19 (IL-19). Breast tissue samples were taken from breast cancer and benign breast lesions patients to isolate and identify bacteria. Based on the obtained results, only 6 out of 30 (20%) cultured breast tissue samples from women with breast cancer showed bacterial growth. In total, 4 (67%) and 2(33%) of these 6 positive cultures were Escherichia coli was and Staphylococcus aureus, respectively, and this relation was statistically significant. However, no bacterial growth was observed on the cultured breast tissue samples taken from women with benign breast lesions. Moreover, the difference between women with a positive and negative result of bacterial culture and stages of breast cancer was statistically non-significant. It is worth mentioning that 50 % of women with breast cancer and bacterial growth were within the age range of 40-49 year. The present study revealed that the difference between women with breast cancer and those with benign breast lesions was statistically highly significant according to the place of residence. In addition, the mean level of IL-19 among women with breast cancer was lower than that in women with benign breast lesions, and this relation was statistically highly significant.

Toll Like Receptors as Sensors of the Tumor Microbial Dysbiosis: Implications in Cancer Progression

The microbiota is a complex ecosystem of active microorganisms resident in the body of mammals. Although the majority of these microorganisms resides in the distal gastrointestinal tract, high-throughput DNA sequencing technology has made possible to understand that several other tissues of the human body host their own microbiota, even those once considered sterile, such as lung tissue. These bacterial communities have important functions in maintaining a healthy body state, preserving symbiosis with the host immune system, which generates protective responses against pathogens and regulatory pathways that sustain the tolerance to commensal microbes. Toll-like receptors (TLRs) are critical in sensing the microbiota, maintaining the tolerance or triggering an immune response through the direct recognition of ligands derived from commensal microbiota or pathogenic microbes. Lately, it has been highlighted that the resident microbiota influences the initiation and development of cancer and its response to therapies and that specific changes in the number and distribution of taxa correlate with the existence of cancers in various tissues. However, the knowledge of functional activity and the meaning of microbiome changes remain limited. This review summarizes the current findings on the function of TLRs as sensors of the microbiota and highlighted their modulation as a reflection of tumor-associated changes in commensal microbiota. The data available to date suggest that commensal "onco-microbes" might be able to break the tolerance of TLRs and become complicit in cancer by sustaining its growth.

Detection of Corynebacterium kroppenstedtii in Granulomatous Lobular Mastitis Using Real-Time Polymerase Chain Reaction and Sanger Sequencing on Formalin-Fixed, Paraffin-Embedded Tissues

CONTEXT.—

Associations between granulomatous lobular mastitis (GLM) and Corynebacterium kroppenstedtii have been reported since 2002, but large scale studies to assess the actual prevalence of this bacterium in GLM have not been performed.

OBJECTIVE.—

To assess the prevalence of C kroppenstedtii in GLM using real-time polymerase chain reaction and Sanger sequencing.

DESIGN.—

We analyzed formalin-fixed, paraffin-embedded tissues from 67 cases of GLM by sequential DNA amplification and sequencing to assess the rate of C kroppenstedtii detection in GLM. A retrospective analysis including patient demographics, history of pregnancy and lactation, clinical signs and symptoms, radiographic findings, histologic pattern, Gram stain results, and microbial cultures was performed on 67 cases of GLM. In addition, 10 cases of nongranulomatous breast abscess were included as controls.

RESULTS.—

C kroppenstedtii 16S rRNA SYBR real-time polymerase chain reaction was positive on formalin-fixed, paraffin-embedded tissues from 46 of 67 (68.7%) GLM cases, while all control cases were negative. Among the positive cases, the majority showed features of cystic neutrophilic granulomatous mastitis.

CONCLUSIONS.—

C kroppenstedtii was highly prevalent in GLM cases and was not found to be associated with nongranulomatous breast abscess in our study (P < .001).

Bacteriophage manipulation of the microbiome associated with tumour microenvironments-can this improve cancer therapeutic response?

Some cancer treatment failures have been attributed to the tumour microbiota, with implications that microbiota manipulation may improve treatment efficacy. While antibiotics have been used to control bacterial growth, their dysbiotic effects on the microbiome, failure to penetrate biofilms and decreased efficacy due to increasing antimicrobial resistance by bacteria, suggest alternatives are needed. Bacteriophages may provide a precise means for targeting oncobacteria whose relative abundance is increased in tumour tissue microbiomes. Fusobacterium, Streptococcus, Peptostreptococcus, Prevotella, Parvimonas, and Treponema species are prevalent in tumour tissue microbiomes of some cancers. They may promote cancer growth by dampening immunity, stimulating release of proinflammatory cytokines, and directly interacting with cancer cells to stimulate proliferation. Lytic bacteriophages against some of these oncobacteria have been isolated and characterised. The search continues for others. The possibility exists for their testing as adjuncts to complement existing therapies. In this review, we highlight the role of oncobacteria, specifically those whose relative abundance in the intra-tumour microbiome is increased, and discuss the potential for bacteriophages against these micro-organisms to augment existing cancer therapies. The capacity for bacteriophages to modulate immunity and kill specific bacteria makes them suitable candidates to manipulate the tumour microbiome and negate the effects of these oncobacteria.

Refining patient selection for breast cancer immunotherapy: beyond PD-L1

Therapies that modulate immune response to cancer, such as immune checkpoint inhibitors, began an intense development a few years ago; however, in breast cancer (BC), the results have been relatively disappointing so far. Finding biomarkers for better selection of BC patients for various immunotherapies remains a significant unmet medical need. At present, only tumour tissue programmed death-ligand 1 (PD-L1) and mismatch repair deficiency status are approved as theranostic biomarkers for programmed cell death-1 (PD-1)/PD-L1 inhibitors in BC. However, due to the complexity of tumour microenvironment (TME) and cancer response to immunomodulators, none of them is a perfect selector. Therefore, an intense quest is ongoing for complementary tumour- or host-related predictive biomarkers in breast immuno-oncology. Among the upcoming biomarkers, quantity, immunophenotype and spatial distribution of tumour-infiltrating lymphocytes and other TME cells as well as immune gene signatures emerge as most promising and are being increasingly tested in clinical trials. Biomarkers or strategies allowing dynamic assessment of BC response to immunotherapy, such as circulating/exosomal PD-L1, quantity of white/immune blood cell subpopulations and molecular imaging are particularly suitable for immunotreatment monitoring. Finally, host-related factors, such as microbiome and lifestyle, should also be taken into account when planning integration of immunomodulating therapies into BC management. As none of the biomarkers taken separately is accurate enough, the solution could come from composite biomarkers, which would combine clinical, molecular and immunological features of the disease, possibly powered by artificial intelligence.

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At present, immune checkpoint inhibitors (ICIs) are the only approved immunotherapy drugs in BC.

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Tumour PD-L1 and microsatellite status are current companion biomarkers for ICIs in BC; however, these need improvement.

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Evaluation of tumour immune contexture and the dynamics of circulating immune cell counts are promising novel approaches.

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Development of noninvasive monitoring and composite biomarkers will facilitate cancer immunotherapy, including in BC.

Prognostic correlations with the microbiome of breast cancer subtypes

Alterations to the natural microbiome are linked to different diseases, and the presence or absence of specific microbes is directly related to disease outcomes. We performed a comprehensive analysis with unique cohorts of the four subtypes of breast cancer (BC) characterized by their microbial signatures, using a pan-pathogen microarray strategy. The signature (includes viruses, bacteria, fungi, and parasites) of each tumor subtype was correlated with clinical data to identify microbes with prognostic potential. The subtypes of BC had specific viromes and microbiomes, with ER+ and TN tumors showing the most and least diverse microbiome, respectively. The specific microbial signatures allowed discrimination between different BC subtypes. Furthermore, we demonstrated correlations between the presence and absence of specific microbes in BC subtypes with the clinical outcomes. This study provides a comprehensive map of the oncobiome of BC subtypes, with insights into disease prognosis that can be critical for precision therapeutic intervention strategies.

Breast and gut microbiome in health and cancer

The microbiota plays essential roles in health and disease, in both the intestine and the extra-intestine. Dysbiosis of the gut microbiota causes dysfunction in the intestine, which leads to inflammatory, immune, and infectious diseases. Dysbiosis is also associated with diseases beyond the intestine via microbial translocation or metabolisms. The in situ breast microbiome, which may be sourced from the gut through lactation and sexual contact, could be altered and cause breast diseases. In this review, we summarize the recent progress in understanding the interactions among the gut microbiome, breast microbiome, and breast diseases. We discuss the intestinal microbiota, microbial metabolites, and roles of microbiota in immune system. We emphasize the novel roles and mechanisms of the microbiome (both in situ and gastrointestinal sourced) and bacterial products in the development and progression of breast cancer. The intestinal microbial translocation suggests that the gut microbiome is translocated to the skin and subsequently to the breast tissue. The gut bacterial translocation is also due to the increased intestinal permeability. The breast and intestinal microbiota are important factors in maintaining healthy breasts. Micronutrition queuine (Q) is derived from a de novo synthesized metabolite in bacteria. All human cells use queuine and incorporate it into the wobble anticodon position of specific transfer RNAs. We have demonstrated that Q modification regulates genes critical in tight junctions and migration in human breast cancer cells and a breast tumor model. We further discuss the challenges and future perspectives that can move the field forward for prevention, diagnosis, and treatment of breast diseases.

Paradigm shift in the pathogenesis and treatment of oral cancer and other cancers focused on the oralome and antimicrobial-based therapeutics

The oral microbiome is a community of microorganisms, comprised of bacteria, fungi, viruses, archaea, and protozoa, that form a complex ecosystem within the oral cavity. Although minor perturbations in the environment are frequent and compensable, major shifts in the oral microbiome can promote an unbalanced state, known as dysbiosis. Dysbiosis can promote oral diseases, including periodontitis. In addition, oral dysbiosis has been associated with other systemic diseases, including cancer. The objective of this review is to evaluate the epidemiologic evidence linking periodontitis to oral, gastrointestinal, lung, breast, prostate, and uterine cancers, as well as describe new evidence and insights into the role of oral dysbiosis in the etiology and pathogenesis of the cancer types discussed. Finally, we discuss how antimicrobials, antimicrobial peptides, and probiotics may be promising tools to prevent and treat these cancers, targeting both the microbes and associated carcinogenesis processes. These findings represent a novel paradigm in the pathogenesis and treatment of cancer focused on the oral microbiome and antimicrobial‐based therapies.

Uncovering Microbial Composition in Human Breast Cancer Primary Tumour Tissue Using Transcriptomic RNA-seq

Recent research studies are showing breast tissues as a place where various species of microorganisms can thrive and cannot be considered sterile, as previously thought. We analysed the microbial composition of primary tumour tissue and normal breast tissue and found differences between them and between multiple breast cancer phenotypes. We sequenced the transcriptome of breast tumours and normal tissues (from cancer-free women) of 23 individuals from Slovakia and used bioinformatics tools to uncover differences in the microbial composition of tissues. To analyse our RNA-seq data (rRNA depleted), we used and tested Kraken2 and Metaphlan3 tools. Kraken2 has shown higher reliability for our data. Additionally, we analysed 91 samples obtained from SRA database, originated in China and submitted by Sichuan University. In breast tissue, the most enriched group were Proteobacteria, then Firmicutes and Actinobacteria for both datasets, in Slovak samples also Bacteroides, while in Chinese samples Cyanobacteria were more frequent. We have observed changes in the microbiome between cancerous and healthy tissues and also different phenotypes of diseases, based on the presence of circulating tumour cells and few other markers.

The Role of Chronic Inflammation in the Development of Breast Cancer

Chronic inflammation contributes to the malignant transformation of several malignancies and is an important component of breast cancer. The role of chronic inflammation in the initiation and development of breast cancer from normal breast tissue, however, is unclear and needs to be clarified. A review of the literature was conducted to define the chronic inflammatory processes in normal breast tissue at risk for breast cancer and in breast cancer, including the role of lymphocyte and macrophage infiltrates, chronic active adipocytes and fibroblasts, and processes that may promote chronic inflammation including the microbiome and factors related to genomic abnormalities and cellular injury. The findings indicate that in healthy normal breast tissue there is systemic evidence to suggest inflammatory changes are present and associated with breast cancer risk, and adipocytes and crown-like structures in normal breast tissue may be associated with chronic inflammatory changes. The microbiome, genomic abnormalities, and cellular changes are present in healthy normal breast tissue, with the potential to elicit inflammatory changes, while infiltrating lymphocytes are uncommon in these tissues. Chronic inflammatory changes occur prominently in breast cancer tissues, with important contributions from tumor-infiltrating lymphocytes and tumor-associated macrophages, cancer-associated adipocytes and crown-like structures, and cancer-associated fibroblasts, while the microbiome and DNA damage may serve to promote inflammatory events. Together, these findings suggest that chronic inflammation may play a role in influencing the initiation, development and conduct of breast cancer, although several chronic inflammatory processes in breast tissue may occur later in breast carcinogenesis.

Fungi, host immune response, and tumorigenesis

Advances in -omics analyses have tremendously enhanced our understanding of the role of the microbiome in human health and disease. Most research is focused on the bacteriome, but scientists have now realized the significance of the virome and microbial dysbiosis as well, particularly in noninfectious diseases such as cancer. In this review, we summarize the role of mycobiome in tumorigenesis, with a dismal prognosis, and attention to pancreatic ductal adenocarcinoma (PDAC). We also discuss bacterial and mycobial interactions to the host's immune response that is prevalently responsible for resistance to cancer therapy, including immunotherapy. We reported that the Malassezia species associated with scalp and skin infections, colonize in human PDAC tumors and accelerate tumorigenesis via activating the C3 complement-mannose-binding lectin (MBL) pathway. PDAC tumors thrive in an immunosuppressive microenvironment with desmoplastic stroma and a dysbiotic microbiome. Host-microbiome interactions in the tumor milieu pose a significant threat in driving the indolent immune behavior of the tumor. Microbial intervention in multimodal cancer therapy is a promising novel approach to modify an immunotolerant ("cold") tumor microenvironment to an immunocompetent ("hot") milieu that is effective in eliminating tumorigenesis.

Is the skin microbiota a modifiable risk factor for breast disease?: A systematic review

PURPOSE

High prevalence, unreliable risk discrimination and poor clinical outcomes are observed in malignant and benign breast diseases (BD). The involvement of microbial communities in the development of BD has become topical, and distal influences of microbial dysregulation in the breast have been well established. Despite advances, the role of the breast skin microbiota in BD remains unclear. Interactions between the skin microbiota and the underlying mucosal immune system are complex. In homeostasis, the skin offers a physical barrier protecting underlying breast tissue from skin commensals and noxious environmental triggers. Our review aims to illuminate the role of the skin microbiota in the development of BD.

METHODS

Adhering to the PRISMA protocol, a systematic review was conducted utilising the Medline and Embase search engines.

RESULTS

Through a comprehensive search of the last ten years, twenty-two studies satisfied the inclusion criteria. Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were identified as the most prevalent phyla of both breast tissue and skin in healthy controls and BD. High abundance of skin commensals, specifically some species of Staphylococcus, have been linked in breast cancer and metastases. Similarly, dysregulated microbial abundance is also seen in inflammatory and implant-associated BD. These findings raise the hypothesis that the skin microbiota plays a role in tissue homeostasis and may contribute to a range of breast pathologies. Several mechanisms of microbial transfer to underlying tissue have been proposed, including retrograde transfer through ductal systems, breakdown of the skin barrier, and migration through nipple-aspirate fluid.

CONCLUSION

Our review provides preliminary insights into the skin microbiota as a modifiable risk factor for BD. This raises opportunities for future studies in antimicrobials/probiotics as an adjunct to, or replacement of surgery; a diagnostic and/or prognostic tool for BD; and the possibility of conditioning the microbiota to manage BD.

Tumor-related Microbiome in the Breast Microenvironment and Breast Cancer

Despite the significant progress in diagnosis and treatment over the past years in the understanding of breast cancer pathophysiology, it remains one of the leading causes of mortality worldwide among females. Novel technologies are needed to improve better diagnostic and therapeutic approaches, and to better understand the role of tumor-environment microbiome players involved in the progression of this disease. The gut environment is enriched with over 100 trillion microorganisms, which participate in metabolic diseases, obesity, and inflammation, and influence the response to therapy. In addition to the direct metabolic effects of the gut microbiome, accumulating evidence has revealed that a microbiome also exists in the breast and in breast cancer tissue. This microbiome enriched in the breast environment and the tumor microenvironment may modulate effects potentially associated with carcinogenesis and therapeutic interventions in breast tissue, which to date have not been properly acknowledged. Herein, we review the most recent works associated with the population dynamics of breast microbes and explore the significance of the microbiome on diagnosis, tumor development, response to chemotherapy, endocrine therapy, and immunotherapy. To overcome the low reproducibility of evaluations of tumor-related microbiome, sequencing technical escalation and machine deep learning algorithms may be valid for standardization of assessment for breast-related microbiome and their applications as powerful biomarkers for prognosis and predictive response in the future.

Impact of the Gut Microbiota Balance on the Health-Disease Relationship: The Importance of Consuming Probiotics and Prebiotics

Gut microbiota is a group of microorganisms that are deposited throughout the entire gastrointestinal tract. Currently, thanks to genomic tools, studies of gut microbiota have pointed towards the understanding of the metabolism of important bacteria that are not cultivable and their relationship with human homeostasis. Alterations in the composition of gut microbiota could explain, at least in part, some epidemics, such as diabetes and obesity. Likewise, dysbiosis has been associated with gastrointestinal disorders, neurodegenerative diseases, and even cancer. That is why several studies have recently been focused on the direct relationship that these types of conditions have with the specific composition of gut microbiota, as in the case of the microbiota-intestine-brain axis. In the same way, the control of microbiota is related to the diet. Therefore, this review highlights the importance of gut microbiota, from its composition to its relationship with the human health-disease condition, as well as emphasizes the effect of probiotic and prebiotic consumption on the balance of its composition.

Gut Microbiota and Gynecological Cancers: A Summary of Pathogenetic Mechanisms and Future Directions

Over the past 20 years, important relationships between the microbiota and human health have emerged. A link between alterations of microbiota composition (dysbiosis) and cancer development has been recently demonstrated. In particular, the composition and the oncogenic role of intestinal bacterial flora has been extensively investigated in preclinical and clinical studies focusing on gastrointestinal tumors. Overall, the development of gastrointestinal tumors is favored by dysbiosis as it leads to depletion of antitumor substances (e.g., short-chain fatty acids) produced by healthy microbiota. Moreover, dysbiosis leads to alterations of the gut barrier, promotes a chronic inflammatory status through activation of toll-like receptors, and causes metabolic and hormonal dysregulations. However, the effects of these imbalances are not limited to the gastrointestinal tract and they can influence gynecological tumor carcinogenesis as well. The purpose of this Review is to provide a synthetic update about the mechanisms of interaction between gut microbiota and the female reproductive tract favoring the development of neoplasms. Furthermore, novel therapeutic approaches based on the modulation of microbiota and their role in gynecological oncology are discussed.

Lipopolysaccharide from the commensal microbiota of the breast enhances cancer growth: role of S100A7 and TLR4

The role of commensal bacterial microbiota in the pathogenesis of human malignancies has been a research field of incomparable progress in recent years. Although breast tissue is commonly assumed to be sterile, recent studies suggest that human breast tissue may contain a bacterial microbiota. In this study, we used an immune‐competent orthotopic breast cancer mouse model to explore the existence of a unique and independent bacterial microbiota in breast tumors. We observed some similarities in breast cancer microbiota with skin; however, breast tumor microbiota was mainly enriched with Gram‐negative bacteria, serving as a primary source of lipopolysaccharide (LPS). In addition, dextran sulfate sodium (DSS) treatment in late‐stage tumor lesions increased LPS levels in the breast tissue environment. We also discovered an increased expression of S100A7 and low level of TLR4 in late‐stage tumors with or without DSS as compared to early‐stage tumor lesions. The treatment of breast cancer cells with LPS increased the expression of S100A7 in breast cancer cells in vitro. Furthermore, S100A7 overexpression downregulated TLR4 and upregulated RAGE expression in breast cancer cells. Analysis of human breast cancer samples also highlighted the inverse correlation between S100A7 and TLR4 expression. Overall, these findings suggest that the commensal microbiota of breast tissue may enhance breast tumor burden through a novel LPS/S100A7/TLR4/RAGE signaling axis.

Bacterial extracellular vesicles affect endocrine therapy in MCF7 cells

BACKGROUND

: The microbiome is important in the development and progression of breast cancer. This study investigated the effects of microbiome derived from Klebsiella on endocrine therapy of breast cancer using MCF7 cells. The bacterial extracellular vesicles (EVs) that affect endocrine therapy were established through experiments focused on tamoxifen efficacy.

METHODS

: The microbiomes of breast cancer patients and healthy controls were analyzed using next-generation sequencing. Among microbiome, Klebsiella was selected as the experimental material for the effect on endocrine therapy in MCF7 cells. MCF7 cells were incubated with tamoxifen in the absence/presence of bacterial EVs derived from Klebsiella pneumoniae and analyzed by quantitative real-time polymerase chain reaction and Western blot.

RESULTS

: Microbiome derived from Klebsiella is abundant in breast cancer patients especially luminal A subtype compared to healthy controls. The addition of EVs derived from K pneumoniae enhances the anti-hormonal effects of tamoxifen in MCF7 cells. The increased efficacy of tamoxifen is mediated via Cyclin E2 and p-ERK.

CONCLUSION

: Based on experiments, the EVs derived from K pneumoniae are important in hormone therapy on MCF7 cells. This result provides new insight into breast cancer mechanisms and hormone therapy using Klebsiella found in the microbiome.

The microbiome of HPV-positive tonsil squamous cell carcinoma and neck metastasis

BACKGROUND

Oropharyngeal squamous cell carcinoma (OPSCC) has now surpassed cervical cancer as the most common site of HPV-related cancer in the United States. HPV-positive OPSCCs behave differently from HPV-negative tumors and often present with early lymph node involvement. The bacterial microbiome of HPV-associated OPSCC may contribute to carcinogenesis, and certain bacteria may influence the spread of cancer from the primary site to regional lymphatics.

OBJECTIVE

To determine the bacterial microbiome in patients with HPV-associated, early tonsil SCC and compare them to benign tonsil specimens.

METHOD

The microbiome of primary tumor specimens and lymph nodes was compared to benign tonsillectomy specimens with pan-pathogen microarray (PathoChip).

RESULTS

A total of 114 patients were enrolled in the study. Patients with OPSCC had a microbiome that shifted towards more gram-negative. Numerous signatures of bacterial family and species were associated with the primary tumors and lymph nodes of cancer patients, including the urogenital pathogens Proteus mirabilis and Chlamydia trachomatis, Neisseria gonorrhoeae, Shigella dysenteriae, and Orientia tsutsugamushi.

CONCLUSION

Our results suggest that detection of urogenital pathogens is associated with lymph node metastasis for patients with HPV-positive OPSCCs. Additional studies are necessary to determine the effects of the OPSCC microbiome on disease progression and clinical outcomes.

Human breast microbiome correlates with prognostic features and immunological signatures in breast cancer

BACKGROUND

Currently, over half of breast cancer cases are unrelated to known risk factors, highlighting the importance of discovering other cancer-promoting factors. Since crosstalk between gut microbes and host immunity contributes to many diseases, we hypothesized that similar interactions could occur between the recently described breast microbiome and local immune responses to influence breast cancer pathogenesis.

METHODS

Using 16S rRNA gene sequencing, we characterized the microbiome of human breast tissue in a total of 221 patients with breast cancer, 18 individuals predisposed to breast cancer, and 69 controls. We performed bioinformatic analyses using a DADA2-based pipeline and applied linear models with White's t or Kruskal-Wallis H-tests with Benjamini-Hochberg multiple testing correction to identify taxonomic groups associated with prognostic clinicopathologic features. We then used network analysis based on Spearman coefficients to correlate specific bacterial taxa with immunological data from NanoString gene expression and 65-plex cytokine assays.

RESULTS

Multiple bacterial genera exhibited significant differences in relative abundance when stratifying by breast tissue type (tumor, tumor adjacent normal, high-risk, healthy control), cancer stage, grade, histologic subtype, receptor status, lymphovascular invasion, or node-positive status, even after adjusting for confounding variables. Microbiome-immune networks within the breast tended to be bacteria-centric, with sparse structure in tumors and more interconnected structure in benign tissues. Notably, Anaerococcus, Caulobacter, and Streptococcus, which were major bacterial hubs in benign tissue networks, were absent from cancer-associated tissue networks. In addition, Propionibacterium and Staphylococcus, which were depleted in tumors, showed negative associations with oncogenic immune features; Streptococcus and Propionibacterium also correlated positively with T-cell activation-related genes.

CONCLUSIONS

This study, the largest to date comparing healthy versus cancer-associated breast microbiomes using fresh-frozen surgical specimens and immune correlates, provides insight into microbial profiles that correspond with prognostic clinicopathologic features in breast cancer. It additionally presents evidence for local microbial-immune interplay in breast cancer that merits further investigation and has preventative, diagnostic, and therapeutic potential.

Moving with the Times: The Health Science Alliance (HSA) Biobank, Pathway to Sustainability

Human biobanks are recognised as vital components of translational research infrastructure. With the growth in personalised and precision medicine, and the associated expansion of biomarkers and novel therapeutics under development, it is critical that researchers can access a strong collection of patient biospecimens, annotated with clinical data. Biobanks globally are undertaking transformation of their operating models in response to changing research needs; transition from a ‘classic’ model representing a largely retrospective collection of pre-defined specimens to a more targeted, prospective collection model, although there remains a research need for both models to co-exist. Here we introduce the Health Science Alliance (HSA) Biobank, established in 2012 as a classic biobank, now transitioning to a hybrid operational model. Some of the past and current challenges encountered are discussed including clinical annotation, specimen utilisation and biobank sustainability, along with the measures the HSA Biobank is taking to address these challenges. We describe new directions being explored, going beyond traditional specimen collection into areas involving bioimages, microbiota and live cell culture. The HSA Biobank is working in collaboration with clinicians, pathologists and researchers, piloting a sustainable, robust platform with the potential to integrate future needs.

Exploring the Potential of Breast Microbiota as Biomarker for Breast Cancer and Therapeutic Response

Breast cancer tissue contains its own unique microbiota. Emerging preclinical data indicates that breast microbiota dysbiosis contributes to breast cancer initiation and progression. Furthermore, the breast microbiota may be a promising biomarker for treatment selection and prognosis. Differences in breast microbiota composition have been found between breast cancer subtypes and disease severities that may contribute to immunosuppression, enabling tumor cells to evade immune destruction. Interactions between breast microbiota, gut microbiota, and immune system are proposed, all forming potential targets to increase therapeutic efficacy. In addition, because the gut microbiota affects the host immune system and systemic availability of estrogen and bile acids known to influence tumor biology, gut microbiota modulation could be used to manipulate breast microbiota composition. Identifying breast and gut microbial compositions that respond positively to certain anticancer therapeutics could significantly reduce cancer burden. Additional research is needed to unravel the complexity of breast microbiota functioning and its interactions with the gut and the immune system. In this review, developments in the understanding of breast microbiota and its interaction with the immune system and the gut microbiota are discussed. Furthermore, the biomarker potential of breast microbiota is evaluated in conjunction with possible strategies to target microbiota in order to improve breast cancer treatment.

Approaching precision medicine by tailoring the microbiota

Accumulating evidence has revealed the link between the microbiota and various human diseases. Advances in high-throughput sequencing technologies have identified some consistent disease-associated microbial features, leading to the emerging concept of microbiome-based therapeutics. However, it is also becoming clear that there are considerable variations in the microbiota among patients with the same disease. Variations in the microbial composition and function contribute to substantial differences in metabolic status of the host via production of a myriad of biochemically and functionally different microbial metabolites. Indeed, compelling evidence indicates that individuality of the microbiome may result in individualized responses to microbiome-based therapeutics and other interventions. Mechanistic understanding of the role of the microbiota in diseases and drug metabolism would help us to identify causal relationships and thus guide the development of microbiome-based precision or personalized medicine. In this review, we provide an overview of current efforts to use microbiome-based interventions for the treatment of diseases such as cancer, neurological disorders, and diabetes to approach precision medicine.

Comprehensive Analysis of the Effect of Probiotic Intake by the Mother on Human Breast Milk and Infant Fecal Microbiota

BACKGROUND

Human breast milk (HBM) contains optimal nutrients for infant growth. Probiotics are used to prevent disease and, when taken by the mother, they may affect infant microbiome as well as HBM. However, few studies have specifically investigated the effect of probiotic intake by the mother on HBM and infant microbiota at genus/species level. Therefore, we present a comprehensive analysis of paired HBM and infant feces (IF) microbiome samples before and after probiotic intake by HBM-producing mothers.

METHODS

Lactating mothers were administered with Lactobacillus rhamnosus (n = 9) or Saccharomyces boulardii capsules (n = 9), for 2 months; or no probiotic (n = 7). Paired HBM and IF samples were collected before and after treatment and analyzed by next-generation sequencing.

RESULTS

Forty-three HBM and 49 IF samples were collected and sequenced. Overall, in 43 HBM samples, 1,190 microbial species belonging to 684 genera, 245 families, 117 orders, and 56 classes were detected. In 49 IF samples, 372 microbial species belonging to 195 genera, 79 families, 42 orders, and 18 classes were identified. Eight of 20 most abundant genera in both HBM and IF samples overlapped: Streptococcus (14.42%), Lactobacillus, Staphylococcus, and Veillonella, which were highly abundant in the HBM samples; and Bifidobacterium (27.397%), Bacteroides, and Faecalibacterium, which were highly abundant in the IF samples. Several major bacterial genera and species were detected in the HBM and IF samples after probiotic treatment, illustrating complex changes in the microbiomes upon treatment.

CONCLUSION

This is the first Korean microbiome study in which the effect of different probiotic intake by the mother on the microbiota in HBM and IF samples was investigated. This study provides a cornerstone to further the understanding of the effect of probiotics on the mother and infant microbiomes.

The onco-immunological implications of Fusobacterium nucleatum in breast cancer

Breast cancer is a leading cause of death worldwide and a better understanding of this disease is needed to improve treatment outcomes. Recent evidence indicates that bacterial dysbiosis is associated with breast cancer, but the bacteria involved remain poorly characterised. Furthermore, an association between periodontal disease, characterised by oral dysbiosis, and breast cancer have also been discovered, but the mechanisms responsible for this association remains to be elucidated. The oral bacterium involved in periodontal disease, Fusobacterium nucleatum, have recently been detected in human breast tumour tissue and it promoted tumour growth and metastatic progression in a mouse model. The mechanisms of how F. nucleatum might colonise breast tissue and how it might promote tumour progression has not been fully elucidated yet. Here we discuss the breast tumour microbiota, its colonisation by F. nucleatum, possible mechanisms by which F. nucleatum might promote breast cancer progression and how this might impact breast cancer treatment. Literature indicates that F. nucleatum might promote breast cancer progression through activating the Toll-like receptor 4 pathway and by supressing the immune system. This results in cell growth and treatment resistance through autophagy as well as immune evasion. Targeted treatment directed at F. nucleatum combined with immunotherapy and autophagy inhibitors might therefore be a feasible treatment strategy for breast cancer patients.

Human Microbiota and Breast Cancer-Is There Any Relevant Link?-A Literature Review and New Horizons Toward Personalised Medicine

Breast cancer (BC) is the most common malignancy and the second cause of cancer-specific death in women from high-income countries. Recently, gut microbiota dysbiosis emerged as a key player that may directly and/or indirectly influence development, treatment, and prognosis of BC through diverse biological processes: host cell proliferation and death, immune system function, chronic inflammation, oncogenic signalling, hormonal and detoxification pathways. Gut colonisation occurs during the prenatal period and is later diversified over distinct phases throughout life. In newly diagnosed postmenopausal BC patients, an altered faecal microbiota composition has been observed compared with healthy controls. Particularly, β-glucuronidase bacteria seem to modulate the enterohepatic circulation of oestrogens and their resorption, increasing the risk of hormone-dependent BC. Moreover, active phytoestrogens, short-chain fatty acids, lithocholic acid, and cadaverine have been identified as bacterial metabolites influencing the risk and prognosis of BC. As in gut, links are also being made with local microbiota of tumoural and healthy breast tissues. In breast microbiota, different microbial signatures have been reported, with distinct patterns per stage and biological subtype. Total bacterial DNA load was lower in tumour tissue and advanced-stage BC when compared with healthy tissue and early stage BC, respectively. Hypothetically, these findings reflect local dysbiosis, potentially creating an environment that favours breast tumour carcinogenesis (oncogenic trigger), or the natural selection of microorganisms adapted to a specific microenvironment. In this review, we discuss the origin, composition, and dynamic evolution of human microbiota, the links between gut/breast microbiota and BC, and explore the potential implications of metabolomics and pharmacomicrobiomics that might impact BC development and treatment choices toward a more personalised medicine. Finally, we put in perspective the potential limitations and biases regarding the current microbiota research and provide new horizons for stronger accurate translational and clinical studies that are needed to better elucidate the complex network of interactions between host, microorganisms, and drugs in the field of BC.

Bifidobacterium Strain-Specific Enhances the Efficacy of Cancer Therapeutics in Tumor-Bearing Mice

Colorectal cancer (CRC) is among the leading causes of cancer-related death in the world. The development of CRC is associated with smoking, diet, and microbial exposure. Previous studies have shown that dysbiosis of the gut microbiome affects cancer development, because it leads to inflammation and genotoxicity. Supplementation with specific microbiota induces anti-tumor effects by enhancing of anti-tumor immunity. Here, we observed that supplementation with either of two B. breve strains reduces tumor growth in MC38 colon carcinoma-bearing mice. Interestingly, only one B. breve strain boosted the efficacy of cancer therapeutics, including oxaliplatin and PD-1 blockade. Extensive immune profiling and transcriptomic analysis revealed that the boosting B. breve strain augments lymphocyte-mediated anti-cancer immunity. Our results suggest that supplementation with B. breve strains could potentially be used as a strategy to enhance the efficacy of CRC therapeutics.