Association of high-risk human papillomavirus infection duration and cervical lesions with vaginal microbiota composition

Effects of vaginal microbiota on human papillomavirus infection and its related diseases

With the knowledge of female reproductive tract microbiota gradually increasing, the connection between vaginal microbiota (VMB) and its related diseases is increasingly highlighted. Manifestation of VMB keeps changing with various dominated bacteria, which can affect the immune response of mucosal barrier and the entrance of pathogens. Human papillomavirus (HPV), as an oncogenic virus, is closely related to viral-associated cancer, such as cervical cancer. According to HPV infection status, VMB can transform into different types, and result in accelerating or restraining the progression of diseases, which have exposed the inner link between VMB and HPV. Therefore, probiotics therapy promises to be a new complementary therapy to rebuild a healthy VMB for patients, but there's still a long way to go before its ready for the clinic. This review focuses on composition, immune response, and application of VMB in HPV and its associated diseases and aims to provide the new ideas and directions for the research on VMB.

Influence of Microbiota on Tumor Immunotherapy

The role of the microbiome in immunotherapy has recently garnered substantial attention, with molecular studies and clinical trials providing emerging evidence on the pivotal influence of the microbiota in enhancing therapeutic outcomes via immune response modulation. However, the impact of microbial communities can considerably vary across individuals and different immunotherapeutic approaches, posing prominent challenges in harnessing their potential. In this comprehensive review, we outline the current research applications in tumor immunotherapy and delve into the possible mechanisms through which immune function is influenced by microbial communities in various body sites, encompassing those in the gut, extraintestinal barrier, and intratumoral environment. Furthermore, we discuss the effects of diverse microbiome-based strategies, including probiotics, prebiotics, fecal microbiota transplantation, and the targeted modulation of specific microbial taxa, and antibiotic treatments on cancer immunotherapy. All these strategies potentially have a profound impact on immunotherapy and pave the way for personalized therapeutic approaches and predictive biomarkers.

Clinical potential of microbiota in thyroid cancer therapy

Thyroid cancer is one of the most common tumors of the endocrine system because of its rapid and steady increase in incidence and prevalence. In recent years, a growing number of studies have identified a key role for the gut, thyroid tissue and oral microbiota in the regulation of metabolism and the immune system. A growing body of evidence has conclusively demonstrated that the microbiota influences tumor formation, prevention, diagnosis, and treatment. We provide extensive information in which oral, gut, and thyroid microbiota have an effect on thyroid cancer development in this review. In addition, we thoroughly discuss the various microbiota species, their potential functions, and the underlying mechanisms for thyroid cancer. The microbiome offers a unique opportunity to improve the effectiveness of immunotherapy and radioiodine therapy thyroid cancer by maintaining the right type of microbiota, and holds great promise for improving clinical outcomes and quality of life for thyroid cancer patients.

Human Papillomavirus Infections and the Role Played by Cervical and Cervico-Vaginal Microbiota-Evidence from Next-Generation Sequencing Studies

This comprehensive review encompasses studies examining changes in the cervical and cervico-vaginal microbiota (CM and CVM) in relation to human papillomavirus (HPV) using next-generation sequencing (NGS) technology. HPV infection remains a prominent global health concern, with a spectrum of manifestations, from benign lesions to life-threatening cervical cancers. The CM and CVM, a unique collection of microorganisms inhabiting the cervix/vagina, has emerged as a critical player in cervical health. Recent research has indicated that disruptions in the CM and CVM, characterized by a decrease in Lactobacillus and the overgrowth of other bacteria, might increase the risk of HPV persistence and the progression of cervical abnormalities. This alteration in the CM or CVM has been linked to a higher likelihood of HPV infection and cervical dysplasia. NGS technology has revolutionized the study of the cervical microbiome, providing insights into microbial diversity, dynamics, and taxonomic classifications. Bacterial 16S rRNA gene sequencing, has proven invaluable in characterizing the cervical microbiome, shedding light on its role in HPV infections and paving the way for more tailored strategies to combat cervical diseases. NGS-based studies offer personalized insights into an individual's cervical microbiome. This knowledge holds promise for the development of novel diagnostic tools, targeted therapies, and preventive interventions for cervix-related conditions, including cervical cancer.

Vaginal microecology and its role in human papillomavirus infection and human papillomavirus associated cervical lesions

The vaginal microecology comprises the vaginal microbiome, immune microenvironment, vaginal anatomy, and the cervicovaginal fluid, which is rich in metabolites, enzymes, and cytokines. Investigating its role in the female reproductive system holds paramount significance. The advent of next-generation sequencing enabled a more profound investigation into the structure of the vaginal microbial community in relation to the female reproductive system. Human papillomavirus infection is prevalent among women of reproductive age, and persistent oncogenic HPV infection is widely recognized as a factor associated with cervical cancer. Extensive previous research has demonstrated that dysbiosis of vaginal microbiota characterized by a reduction in Lactobacillus species, heightens susceptivity to HPV infection, consequently contributing to persistent HPV infection and the progression of cervical lesion. Likewise, HPV infection can exacerbate dysbiosis. This review aims to provide a comprehensive summary of current literatures and to elucidate potential mechanisms underlying the interaction between vaginal microecology and HPV infection, with the intention of offering valuable insights for future clinical interventions.

Exploring Microbiota Diversity in Cervical Lesion Progression and HPV Infection through 16S rRNA Gene Metagenomic Sequencing

(1) Background: Cervical cancer is a significant health concern, with the main cause being persistent infection with high-risk Human Papillomavirus (hrHPV). There is still no evidence for why viral persistence occurs in some women, but recent studies have revealed the interplay between cervical microbiota and hrHPV. This research aimed to characterize the cervicovaginal microbiota in cervical lesion progression and HPV infection status. (2) Methods: This study included 85 cervical specimens from women from the north-eastern region of Romania. DNA was isolated from cervical secretion for HPV genotyping and 16S ribosomal RNA gene NGS sequencing. (3) Results: Our study revealed a distinct pattern within the studied group when considering Lactobacillus species, which differs from findings reported in other populations. Specifically, the presence of Lactobacillus iners coupled with the absence of Lactobacillus crispatus alongside Atopobium spp., Prevotella spp., and Gardnerella spp. could serve as defining factors for severe cervical lesions. The results also showed a significant association between microbiota diversity, HPV infection, and cervical lesion progression. (4) Conclusions: As the microbiota profile seems to vary among different populations and individuals, a deeper comprehension of its composition has the potential to develop personalized detection and treatment approaches for cervical dysplasia and cancer.

Associations of human papillomavirus genotypes and cervical vascular abnormality in a cohort of women underwent colposcopy, a retrospective study of 6716 patients

Aims

Abnormal vessel patterns are specific signs in patients with early cervical abnormality and cervical cancer(CC) by colposcopy, but the impact of human papillomavirus (HPV) infections on abnormal vessel patterns remains unknown.

Methods

A total of 6716 female patients with HPV infections or cytological abnormalities who underwent a colposcopy following abnormal CC screening results were included in the study. The final pathological diagnosis was confirmed to be the most severe pathological grade across cervical biopsy, endocervical canal curettage (ECC) and conization. Univariate and multivariate logistic regression analyses were used to investigate the association between HPV infections and abnormal vessel patterns, adjusting for age, gravidity and parity.

Results

There were 6124 normal vascular cases by colposcopy and 592 cases with cervical vascular abnormality. The prevalence of HPV infections was 4284 (70%) in normal patients, and the prevalence of HPV infections was 479 (80%) in cervical vascular abnormality patients. HPV high-risk type 16 infection alone increased the risk of cervical heteromorphic blood vessels (aOR=3.66, 95%CI: 2.54~5.27). HPV 16 and 33 alone (other than the commonly recognized subtype of 18) or coinfection of these two genotypes could increase the risk of cervical punctate vascular and cervical vascular mosaic features and abnormal cervical blood vessels. An increased risk of abnormal cervical lesions was observed for HPV 16 and 33 alone or combined in coinfection compared to the negative group. The risk of cervical vascular abnormality was increased 10-fold by coinfection with HPV 16 and 33 (aOR=10.67, 95% CI: 4.54~25.09, P<0.001). HPV 16, 33 alone or combined in coinfection were associated with an increased risk of lesions more advanced than high-grade squamous intraepithelial lesion (HSIL) when compared to the negative group. The risk of lesions more advanced than HSIL was up to 26-fold higher in the coinfection with HPV 16 and 33 group than in the negative group (aOR=26.23, 95%CI: 11.23~61.27, P<0.001).

Conclusion

HPV16 and 33 are the most dangerous HPV genotypes correlated with abnormal vascular patterns. Combined HPV16 and HPV33 infection increases the risk of abnormal vascular patterns. Combined HPV16 and HPV33 infection increases the risk of developing HSIL+.

Cervicovaginal Microbiota Profiles in Precancerous Lesions and Cervical Cancer among Ethiopian Women

Although high-risk human papillomavirus infection is a well-established risk factor for cervical cancer, other co-factors within the local microenvironment may play an important role in the development of cervical cancer. The current study aimed to characterize the cervicovaginal microbiota in women with premalignant dysplasia or invasive cervical cancer compared with that of healthy women. The study comprised 120 Ethiopian women (60 cervical cancer patients who had not received any treatment, 25 patients with premalignant dysplasia, and 35 healthy women). Cervicovaginal specimens were collected using either an Isohelix DNA buccal swab or an Evalyn brush, and ribosomal RNA sequencing was used to characterize the cervicovaginal microbiota. Shannon and Simpson diversity indices were used to evaluate alpha diversity. Beta diversity was examined using principal coordinate analysis of weighted UniFrac distances. Alpha diversity was significantly higher in patients with cervical cancer than in patients with dysplasia and in healthy women (p < 0.01). Beta diversity was also significantly different in cervical cancer patients compared with the other groups (weighted UniFrac Bray-Curtis, p < 0.01). Microbiota composition differed between the dysplasia and cervical cancer groups. Lactobacillus iners was particularly enriched in patients with cancer, and a high relative abundance of Lactobacillus species was identified in the dysplasia and healthy groups, whereas Porphyromonas, Prevotella, Bacteroides, and Anaerococcus species predominated in the cervical cancer group. In summary, we identified differences in cervicovaginal microbiota diversity, composition, and relative abundance between women with cervical cancer, women with dysplasia, and healthy women. Additional studies need to be carried out in Ethiopia and other regions to control for variation in sample collection.

Bacteria and macrophages in the tumor microenvironment

Cancer and microbial infections are significant worldwide health challenges. Numerous studies have demonstrated that bacteria may contribute to the emergence of cancer. In this review, we assemble bacterial species discovered in various cancers to describe their variety and specificity. The relationship between bacteria and macrophages in cancer is also highlighted, and we look for ample proof to establish a biological basis for bacterial-induced macrophage polarization. Finally, we quickly go over the potential roles of metabolites, cytokines, and microRNAs in the regulation of the tumor microenvironment by bacterially activated macrophages. The complexity of bacteria and macrophages in cancer will be revealed as we gain a better understanding of their pathogenic mechanisms, which will lead to new therapeutic approaches for both inflammatory illnesses and cancer.

Prevalence of Human Papillomavirus (HPV) among Females in the General Population of the Split and Dalmatia County and Its Association with Genital Microbiota and Infections: A Prospective Study

We conducted a prospective study with the aim of determining HPV prevalence and type distribution in the general female population of Southern Croatia (SDC), and to detect the presence of other microorganisms in the lower part of the female reproductive system and their possible influence on the frequency of HPV infection. Data were collected during routine check-up exams. All participants were examined by a gynecologist, and cervico-vaginal scrapings/swabs were collected, for cytological (Pap smear) and microbiological (for bacterial growth, genital mycoplasmas, chlamydia, and HPV) analysis. Informed consent was obtained from all participants with accompanying questionnaire. A total of 1050 asymptomatic women living in SDC participated in the study during a one-year period, and 107 of them (10.2%) had HR-HPV infection. We found that the presence of some bacteria (Ureaplasma, Chlamydia, and Gardnerella) in the lower part of the female genital system has a positive correlation with the frequency of HPV infection and, consequently, a possible influence on faster progression to cervical dysplasia caused by HPV. We consider that inclusion of screening for sexually transmitted infections as monitoring in women with HPV infection could help to find women at risk of cervical cancer progression.

Current understanding of the intratumoral microbiome in various tumors

It is estimated that in the future, the number of new cancer cases worldwide will exceed the 19.3 million recorded in 2020, and the number of deaths will exceed 10 million. Cancer remains the leading cause of human mortality and lagging socioeconomic development. Intratumoral microbes have been revealed to exist in many cancer types, including pancreatic, colorectal, liver, esophageal, breast, and lung cancers. Intratumoral microorganisms affect not only the host immune system, but also the effectiveness of tumor chemotherapy. This review concentrates on the characteristics and roles of intratumoral microbes in various tumors. In addition, the potential of therapies targeting intratumoral microbes, as well as the main challenges currently delaying these therapies, are explored. Furthermore, we briefly summarize existing technical methods used to characterize intratumoral microbes. We hope to provide ideas for exploring intratumoral microbes as potential biomarkers and targets for tumor diagnosis, treatment, and prognostication.

The Role of Intratumor Microbiomes in Cervical Cancer Metastasis

BACKGROUND

Intratumor microbiomes can influence tumorigenesis and progression. The relationship between intratumor microbiomes and cervical cancer metastasis, however, remains unclear.

METHODS

We examined 294 cervical cancer samples together with information on microbial expression, identified metastasis-associated microbiomes, and used machine learning methods to validate their predictive ability on tumor metastasis. The tumors were subsequently typed based on differences in microbial expression. Differentially expressed genes in different tumor types were combined to construct a tumor-prognostic risk score model and a multiparameter nomogram model. In addition, we performed a functional enrichment analysis of differentially expressed genes to infer the mechanism of action between microbiomes and tumor cells.

RESULTS

Based on the 15 differentially expressed microbiomes, machine learning models were able to correctly predict the risk of cervical cancer metastasis. In addition, both the risk score and the nomogram model accurately predicted tumor prognosis. Differences in the expression of endogenous genes in tumors can influence the distribution of the intracellular microbiomes.

CONCLUSIONS

Intratumoral microbiomes in cervical cancer are associated with tumor metastasis and influence disease prognosis. A change in gene expression within tumor cells is responsible for differences in the microbial populations within the tumor.

HPV-related cervical diseases: Alteration of vaginal microbiotas and promising potential for diagnosis

Vaginal microbiota is closely associated with women's health, however, the correlation between HPV-related cervical disease (HRCD) and vaginal microbiota is still obscure. In this study, patients with HRCD (n = 98) and healthy controls (n = 58) in Hangzhou were recruited, and their vaginal microbiota were collected and analyzed. The composition of the vaginal microbial community was explored, and a disease classification model was developed by random forest algorithm. The results suggested that the diversity of vaginal microbiota was significantly higher in HRCDs than that in healthy controls (p < 0.05). Firmicutes is the dominant phylum in vaginal microbiota, and Lactobacillus was identified as the most altered genus between two groups (p < 0.01). Kyoto Encyclopedia of Genes and Genomes analysis suggested the difference in vaginal microbial community functions between two groups. Furthermore, we identified 10 biomarkers as the optimal marker sets for the random forest model and found a higher probability of disease values in HRCD group in discovery cohort (p < 0.0001), with an area under the receiver operating characteristic curve reaching 89.7% (95% confidence interval: 78.3%-100%). We further validated the model in both validation and independent diagnosis cohorts, confirming its accuracy in the prediction of HRCD. In conclusion, this study revealed the community composition of vaginal microbiota in HRCDs and successfully constructed a diagnostic model for HRCD.

Characteristics of Vaginal Microbiome in Reproductive-Age Females with HPV Infection in Xinjiang, China

OBJECTIVE

We investigated the characteristics of vaginal microbiome in reproductive-age females with HPV infection in Xinjiang, China.

METHODS

A total of 135 females of reproductive age were enrolled. There were 43 healthy HPV-negative females in control group (N group), 58 HPV-positive females in nonlesion group (P1 group), and 34 HPV-positive females in low-grade squamous intraepithelial lesion group (P2 group). DNA was extracted from the vaginal secretions, and V3-V4 regions of bacterial 16S rDNA were amplified and sequenced by NovaSeq. QIIME2 and R software were used to perform diversity analysis of bacteria. PICRUSt2 was used to predict the function of the vaginal microbiota.

RESULTS

Lactobacillus was the main genus of vaginal microbiota in asymptomatic reproductive-age females with or without HPV in Xinjiang. The diversity of vaginal microbiota in the P1 group was significantly higher than that in the N group, and the proportion of Gardnerella increased significantly. The vaginal microbiota structure of the P2 group was different from the N group, characterized by the decrease of Lactobacillus crispatus and the increase of Shuttleworthia. The function of the inordinate microbiome may play a role in accelerating HPV replication and integration.

CONCLUSION

The structure of vaginal microbiota alters under persistent HPV infection in asymptomatic females of reproductive age in Xinjiang. The Gardnerella increase is associated with increased susceptibility to HPV infection, and Lactobacillus iners predominance and Shuttleworthia presence may be a signature of HPV infection with low-grade squamous intraepithelial lesion.

A comprehensive review of the multifaceted role of the microbiota in human pancreatic carcinoma

Pancreatic carcinoma is associated with one of the worst clinical outcomes throughout the globe because of its aggressive, metastatic, and drug-resistant nature. During the past decade, several studies have shown that oral, gut, and tumor microbiota play a critical role in the modulation of metabolism and immune responses. Growing pieces of evidence have proved beyond a doubt that the microbiota has a unique ability to influence the tumor microenvironment as well as the metabolism of chemotherapeutic agents or drugs. Given this, microbiota, known as the ecological community of microorganisms, stands to be an avenue of quality research. In this review, we provide detailed and critical information on the role of oral, gut, and pancreatic microbiota disruptions in the development of pancreatic carcinoma. Moreover, we comprehensively discuss the different types of microbiota, their potential role, and mechanism associated with pancreatic carcinoma. The microbiome provides the unique opportunity to enhance the effectiveness of chemotherapeutic agents and immunotherapies for pancreatic cancer by maintaining the right type of microbiota and holds a promising future to enhance the clinical outcomes of patients with pancreatic carcinoma.

Cervicovaginal microbiota significantly changed for HPV-positive women with high-grade squamous intraepithelial lesion

Lower female genital tract is colonized by a variety of microbes (cervicovaginal microbiota, CVM) which associate with the risk of genital infection. This study characterized CVM for 149 Chinese women with different status of human papillomavirus (HPV) infection and squamous intraepithelial lesion (SIL): no HPV infection (HPV-), HPV infection without significant SIL (HPV+NoSIL), HPV infection with low-grade SIL (HPV+LSIL) and HPV infection with high-grade SIL (HPV+HSIL). Analysis results showed CVM has dramatically changed in HPV+HSIL group when compared to HPV+LSIL group, but it exhibited no significant differences between HPV- and HPV+NoSIL groups as well as between HPV+NoSIL and HPV+LSIL groups. In consistence, random forest analysis found more notable differences in HPV+HSIL vs HPV+LSIL comparison than in other comparisons. In addition, depletion of Lactobacillus in CVM was more to be frequently identified in SIL-positive women as compared to SIL-negative individuals. Our findings suggested that significant CVM differences occurred when SIL developed to HSIL which was caused by persistent HPV infection.

The role of probiotics in vaginal health

Probiotics have been widely used in the treatment of intestinal diseases, but the effect of probiotics on female reproductive tract health is still controversial. Lactobacillus is the most abundant microorganism in the vagina, which is related to the vaginal mucosal barrier. Lactobacillus adheres to the vaginal epithelium and can competitively antagonize the colonization of pathogens. The factors produced by Lactobacillus, such as bacteriocin and hydrogen peroxide (H₂O₂), can inhibit the growth of pathogenic microorganisms and maintain the low pH environment of the vagina. Probiotics play an important role in maintaining the stability of vaginal microenvironment, improving immune defense and blocking the progression of cervical cancer. We review the research progress of probiotics represented by Lactobacillus in gynecological diseases such as human papilloma virus (HPV) infection, bacterial vaginosis (BV) and Genitourinary Syndrome of Menopause (GSM), so as to provide basis for further exerting the role of probiotics in women’s health.

Disturbances of Vaginal Microbiome Composition in Human Papillomavirus Infection and Cervical Carcinogenesis: A Qualitative Systematic Review

Background

Emerging evidence has demonstrated a close association between perturbations in vaginal microbiota composition in women and human papillomavirus (HPV) infection, cervical lesions, and cervical cancer (Ca); however, these findings are highly heterogeneous and inconclusive.

Aim

To perform a comprehensive systematic review of the global disturbance in the vaginal microbiota, specifically in women with HPV-associated cervical diseases, and to further conduct within- and across-disease comparisons.

Method

Twenty-two records were identified in a systematic literature search of PubMed, Web of Science, and Embase up to February 28, 2022. We extracted microbial changes at the community (alpha and beta diversity) and taxonomic (relative abundance) levels. Within- and across-disease findings on the relative abundance of taxonomic assignments were qualitatively synthesized.

Results

Generally, significantly higher alpha diversity was observed for HPV infection, cervical lesions, and/or cancer patients than in controls, and significant differences within beta diversity were observed for the overall microbial composition across samples. In within-disease comparisons, the genera Gardnerella, Megasphaera, Prevotella, Peptostreptococcus, and Streptococcus showed the greatest abundances with HPV infection; Sneathia and Atopobium showed inconsistent abundance with HPV infection, and Staphylococcus was observed in Ca. Across diseases, we find increased levels of Streptococcus and varying levels of Gardnerella were shared across HPV infections, high-grade squamous intraepithelial lesions, and Ca, whereas Lactobacillus iners varied depending on the HPV-related disease subtype.

Conclusions

This systematic review reports that vaginal microbiome disturbances are correlated to the depletion of Lactobacillus, enrichment of anaerobes, and increased abundance of aerobic bacteria in HPV infection and related cervical diseases. Moreover, L. iners may exert either protective or pathogenic effects on different HPV-related diseases.

Genital Microbiota of Women From Six Ethnic Groups With and Without Human Papillomavirus Infection in Shangri-La, China

Background

A diversity of microorganisms is associated with human health and exists in a state of dynamic equilibrium. This diversity has direct implications for the assessment of susceptibility to infectious diseases, especially human papillomavirus (HPV) infection.

Methods

Here, we investigated the relationships between HPV infection and vaginal, cervical, and gut microbiota composition and assessed the levels of genital immune mediators. We selected a multiethnic area in Yunnan Province, China, to collect samples from healthy women of childbearing age. A total of 82 healthy women of childbearing age were included in this study. Vaginal, cervical, and rectal swabs were collected to analyze the microbial community, and cytokines were analyzed in some samples.

Findings

Different proportions and types of HPV infection were detected in cervical (44%), vaginal (18%), and rectal (18%) swabs. HPV detected in cervical swabs was generally a high-risk type, while low-risk HPV types were primarily detected in vaginal and rectal swabs. There were some differences in this proportion as well as in the microbial community composition among different ethnic groups. Rectal samples exhibited the highest diversity index, while vaginal samples displayed the lowest diversity index. Lactobacillus dominated most of the vaginal samples, was decreased in HPV-positive samples, and differed among different ethnic groups. However, the sequence proportion of Lactobacillus in the cervix exhibited the opposite trend in those affected by HPV infection. The dynamic balance between the potential pathogens Gardnerella and Lactobacillus determines the health of the female genital system.

Interpretation

This study constitutes the first step toward personalized medicine for women’s reproductive health, wherein differences between the genital microbiomes of individuals would be considered in risk assessment and for subsequent disease diagnosis and treatment.

Gynecology Meets Big Data in the Disruptive Innovation Medical Era: State-of-Art and Future Prospects

Tremendous scientific and technological achievements have been revolutionizing the current medical era, changing the way in which physicians practice their profession and deliver healthcare provisions. This is due to the convergence of various advancements related to digitalization and the use of information and communication technologies (ICTs)—ranging from the internet of things (IoT) and the internet of medical things (IoMT) to the fields of robotics, virtual and augmented reality, and massively parallel and cloud computing. Further progress has been made in the fields of addictive manufacturing and three-dimensional (3D) printing, sophisticated statistical tools such as big data visualization and analytics (BDVA) and artificial intelligence (AI), the use of mobile and smartphone applications (apps), remote monitoring and wearable sensors, and e-learning, among others. Within this new conceptual framework, big data represents a massive set of data characterized by different properties and features. These can be categorized both from a quantitative and qualitative standpoint, and include data generated from wet-lab and microarrays (molecular big data), databases and registries (clinical/computational big data), imaging techniques (such as radiomics, imaging big data) and web searches (the so-called infodemiology, digital big data). The present review aims to show how big and smart data can revolutionize gynecology by shedding light on female reproductive health, both in terms of physiology and pathophysiology. More specifically, they appear to have potential uses in the field of gynecology to increase its accuracy and precision, stratify patients, provide opportunities for personalized treatment options rather than delivering a package of “one-size-fits-it-all” healthcare management provisions, and enhance its effectiveness at each stage (health promotion, prevention, diagnosis, prognosis, and therapeutics).

The microbiome and human cancer

Microbial roles in cancer formation, diagnosis, prognosis, and treatment have been disputed for centuries. Recent studies have provocatively claimed that bacteria, viruses, and/or fungi are pervasive among cancers, key actors in cancer immunotherapy, and engineerable to treat metastases. Despite these findings, the number of microbes known to directly cause carcinogenesis remains small. Critically evaluating and building frameworks for such evidence in light of modern cancer biology is an important task. In this Review, we delineate between causal and complicit roles of microbes in cancer and trace common themes of their influence through the host's immune system, herein defined as the immuno-oncology-microbiome axis. We further review evidence for intratumoral microbes and approaches that manipulate the host's gut or tumor microbiome while projecting the next phase of experimental discovery.