Can Smoking Cause Differences in Urine Microbiome in Male Patients With Bladder Cancer? A Retrospective Study

Microbiome landscapes of the bladder, intestine, and vagina in bladder cancer: a systematic review

BACKGROUND

Microbiomes have been linked to oncogenesis, e.g. the intestinal microbiome and colon cancer or HPV-associated cervical cancer. A connection between microbiomes of different body cavities and tumor oncogenesis was shown. The gut microbiome's influence on bladder cancer was established, raising the question whether nearby microbiomes (rectum, vagina) also influence bladder cancer due to their proximity.

OBJECTIVE

Considering the influence of various body cavities and the broader microbial components, this systematic review aims to investigate differences in the bladder, vaginal, and intestinal microbiota-including bacterial, viral, fungal and archaea-between patients with bladder cancer and healthy controls.

METHODS

Databases (PubMed, Scopus, Embase) were searched until April 2022. Three types of studies were included: "(1) studies using bladder cancer and control groups (case-controlled studies) (2) studies that provided information on the presence or abundance of microbial taxa (3) studies that provided information on increased or decreased taxa in bladder cancer and/or control groups.". Risk of bias was assessed using the Newcastle Ottawa Scale.

RESULTS

Fourteen studies (695 samples: 403 bladder cancer, 292 controls) were analyzed. Bacterial taxa that have been detected in at least two studies, the genera Geobacillus and Rubrobacter were more frequently in bladder cancer patients; while Streptococcus and Roseomonas were more prevalent in controls. No consistent taxa were identified across stool or bladder tissue samples.

CONCLUSION

The microbiota in bladder cancer patients show significant variation across studies. Standardized methods and expanded investigations into viral and fungal components are needed to clarify the role of microbiota in bladder cancer.

Hot Spots in Urogenital Basic Cancer Research and Clinics

Urogenital cancer is very common in the male population of Western countries, a problem of major concern for public health systems, and a frequent test subject for oncological research. In this narrative, we identify the main hot topics for clinics and the basic science of urological cancer in the last few years (from 2021 onwards), considering the information given in the abstracts of almost 300 original articles published in outstanding journals of pathology, urology, and basic science. Once defined, for the top ten list of hot topics (the 2022 WHO update on the classification of urinary and male genital tumors, new entities in kidney cancer, urinary cancer-omics, update on the Gleason grading system, targeted therapies and other novel therapies in renal cancer, news on non-muscle invasive urothelial carcinoma, artificial intelligence in urologic cancer, intratumor heterogeneity influence in therapeutic failures in urologic neoplasms, intratumor microbiome and its influence in urologic tumor aggressiveness, and ecological principles and mathematics applied to urogenital cancer study), each issue is independently reviewed in an attempt to put together the most relevant updates and/or useful features accompanied by selected illustrations. This review article addresses some of the most interesting and current hot spots in urogenital basic cancer research and clinics and is mainly aimed toward clinicians, including pathologists, urologists, and oncologists. Readers are invited to explore each topic for further, more detailed information, in addition to the references provided.

Gut microbiota influence on lung cancer risk through blood metabolite mediation: from a comprehensive Mendelian randomization analysis and genetic analysis

Background

Gut microbiota (GM) and metabolic alterations play pivotal roles in lung cancer (LC) development and host genetic variations are known to contribute to LC susceptibility by modulating the GM. However, the causal links among GM, metabolite, host genes, and LC remain to be fully delineated.

Method

Through bidirectional MR analyses, we examined the causal links between GM and LC, and utilized two-step mediation analysis to identify potential mediating blood metabolite. We employed diverse MR methods, including inverse-variance-weighted (IVW), weighted median, MR-Egger, weighted mode, and simple mode, to ensure a robust examination of the data. MR-Egger intercept test, Radial MR, MR-PRESSO, Cochran Q test and Leave-one-out (LOO) analysis were used for sensitivity analyses. Analyses were adjusted for smoking, alcohol intake frequency and air pollution. Linkage disequilibrium score regression and Steiger test were used to probe genetic causality. The study also explored the association between specific host genes and the abundance of gut microbes in LC patients.

Results

The presence of Bacteroides clarus was associated with an increased risk of LC (odds ratio [OR] = 1.07, 95% confidence interval [CI]: 1.03-1.11, p = 0.012), whereas the Eubacteriaceae showed a protective effect (OR = 0.82, 95% CI: 0.75-0.89, p = 0.001). These findings remained robust after False Discovery Rate (FDR) correction. Our mediator screening identified 13 blood metabolites that significantly influence LC risk after FDR correction, underscoring cystine and propionylcarnitine in reducing LC risk, while linking specific lipids and hydroxy acids to an increased risk. Our two-step mediation analysis demonstrated that the association between the bacterial pathway of synthesis of guanosine ribonucleotides and LC was mediated by Fructosyllysine, with mediated proportions of 11.38% (p = 0.037). LDSC analysis confirmed the robustness of these associations. Our study unveiled significant host genes ROBO2 may influence the abundance of pathogenic gut microbes in LC patients. Metabolic pathway analysis revealed glutathione metabolism and glutamate metabolism are the pathways most enriched with significant metabolites related to LC.

Conclusion

These findings underscore the importance of GM in the development of LC, with metabolites partly mediating this effect, and provide dietary and lifestyle recommendations for high-risk lung cancer populations.

A review of urinary bladder microbiome in patients with bladder cancer and its implications in bladder pathogenesis

PURPOSE

The recent discovery of the urinary microbiome has led to an emerging field of investigation about the potential role of microorganisms in the pathogenesis of urinary bladder cancer. Few preliminary data have been reported so far implicating urobiome as causative and prognostic factor of bladder tumorigenesis. In the present study, a review of the current evidence is presented about microbiome composition among patients with bladder cancer and healthy individuals as well as possible implications of microbiome on urothelial carcinoma of the bladder.

METHODS

A literature review was conducted using PubMed/MEDLINE, Scopus, and the Cochrane library until December 2023. Search algorithm was constructed using the following terms and their associated Mesh terms and Boolean operators: "urinary microbiome" and "urinary microbiota". Studies written in English language, identifying, and comparing urinary microbiome among bladder cancer patients and healthy control group were included in the review.

RESULTS

A total of 2,356 reports were identified. From this total 16 articles complied with the inclusion criteria were selected for analysis. These articles represent a total of about 486 bladder cancer patients.

CONCLUSION

Recent studies revealed the colonization of the urinary tract and the bladder by micro-organisms using both enhanced culture- and molecular-based techniques for microbial characterization. However, several limitations exist in the literature decreasing the reliability of the current reports. As a result, urinary microbiome consist an ambitious era in bladder cancer research with an increasing number of evidence about its potential pathogenetic, prognostic and therapeutic role.

The Urinary Microbiome in Health and Disease: Relevance for Bladder Cancer

Bladder cancer (BC) constitutes one of the most diagnosed types of cancer worldwide. Advancements in and new methodologies for DNA sequencing, leading to high-throughput microbiota testing, have pinpointed discrepancies in urinary microbial fingerprints between healthy individuals and patients with BC. Although several studies suggest an involvement of microbiota dysbiosis in the pathogenesis, progression, and therapeutic response to bladder cancer, an established direct causal relationship remains to be elucidated due to the lack of standardized methodologies associated with such studies. This review compiles an overview of the microbiota of the human urinary tract in healthy and diseased individuals and discusses the evidence to date on microbiome involvement and potential mechanisms by which the microbiota may contribute to the development of BC. We also explore the potential profiling of urinary microbiota as a biomarker for risk stratification, as well as the prediction of the response to intravesical therapies and immunotherapy in BC patients. Further investigation into the urinary microbiome of BC patients is imperative to unravel the complexities of the role played by host-microbe interactions in shaping wellness or disease and yield valuable insights into and strategies for the prevention and personalized treatment of BC.

Inflammatory bowel disease and bladder cancer risk: based on a Mendelian randomization study

BACKGROUND

Prior epidemiological observational studies have duly documented a correlative link between inflammatory bowel disease (IBD) and bladder cancer (BC); however, the establishment of a definitive causal relationship has remained elusive. The principal objective of this meticulous investigation was to rigorously evaluate the causal nexus between IBD and BC, employing the robust methodology of Mendelian randomization (MR) analysis.

METHODS

We meticulously performed both univariate and multivariate Mendelian randomization (MVMR) analyses employing publicly accessible genome-wide association study (GWAS) data. The central approach employed for our investigations was inverse variance weighting (IVW) method, while diligently scrutinizing potential sources of heterogeneity and horizontal pleiotropy via the rigorous utilization of Cochran's Q test, the MR-PRESSO method, and MR-Egger.

RESULTS

In the univariate MR analysis, no causal link was observed between genetic prediction of IBD and BC. Furthermore, both Crohn's disease (CD) and ulcerative colitis (UC) showed no causal association with BC. The consistent association between CD and UC in the MVMR analysis supports this finding.

CONCLUSION

This study found no genetic basis for the causative association of IBD and BC. It is crucial to emphasize that further comprehensive investigations are warranted to delve into the intricate underlying mechanisms that may contribute to these associations.

Is the Urinary and Gut Microbiome Associated With Bladder Cancer?

Background

Microbiome dysbiosis plays a role in the pathogenesis of many urological diseases, including bladder cancer (BC). The aim of the study was to compare the urinary and gut microbiota of patients with BC with a healthy control (HC) group.

Methods

The study group included patients hospitalized in 2020 to 2021 with diagnosed BC and HC. Prior to the transurethral resection of bladder tumor, patients collected their urine and stool which was then subjected to 16S rRNA gene sequencing.

Results

Overall, 25 patients were enrolled in the study: 18 in the BC group and 7 in the HC group. Analysis of the urine and stool microbiome showed no statistically significant differences between patients with BC and HC in alpha diversity, beta diversity, and difference in taxa relative abundance. Detailed analysis of urine and stool microbiome depending on patient- and tumor-related characteristics also showed no statistically significant differences in alpha diversity and beta diversity. Differences in abundance (ANCOM) were noted in both types of samples in patients with BC. In the urine test, genus Lactobacillus was more common in patients with a positive history of Bacillus Calmette-Guérin (BCG) therapy, while genus Howardella and the strain Streptococcus anginosus were more common in women. In stool samples, abundance of phylum Desulfobacterota was most abundant in Grade G1 and least in G2. Class Alphaproteobacteria, order Rhodospirillales, order Flavobacteriales, and family Flavobacteriaceae were more common in women.

Conclusions

The microbiome of urine and stool of patients with BC does not differ significantly from that of HC; however, its composition in patients with BC varies according to the patient's sex.

From mucosal infection to successful cancer immunotherapy

The clinical management of advanced malignancies of the upper and lower urinary tract has been revolutionized with the advent of immune checkpoint blockers (ICBs). ICBs reinstate or bolster pre-existing immune responses while creating new T cell specificities. Immunogenic cancers, which tend to benefit more from immunotherapy than cold tumours, harbour tumour-specific neoantigens, often associated with a high tumour mutational burden, as well as CD8+ T cell infiltrates and ectopic lymphoid structures. The identification of beneficial non-self tumour antigens and natural adjuvants is the focus of current investigation. Moreover, growing evidence suggests that urinary or intestinal commensals, BCG and uropathogenic Escherichia coli influence long-term responses in patients with kidney or bladder cancer treated with ICBs. Bacteria infecting urothelium could be a prominent target for T follicular helper cells and B cells, linking innate and cognate CD8+ memory responses. In the urinary tract, commensal flora differ between healthy and tumoural mucosae. Although antibiotics can affect the prognosis of urinary tract malignancies, bacteria can have a major influence on cancer immunosurveillance. Beyond their role as biomarkers, immune responses against uropathogenic commensals could be harnessed for the design of future immunoadjuvants that can be advantageously combined with ICBs.

Urinary Microbiome in Bladder Diseases-Review

The microbiome is the totality of microorganisms found in a specific biological niche. It has been proven that in the human body, the microbiome is responsible for its proper functioning. Dysbiosis, i.e., a disturbance in the composition of the microbiome, may be associated with the pathogenesis of many human diseases. Until recently, studies did not focus on the microbiome of the urinary tract, because, since the 19th century, there had been a dogma that urine in healthy people is sterile. Yet, advances in molecular biology techniques have allowed this dogma to be overthrown. The use of DNA sequencing has shown that the urinary tract has its own endogenous microbiome. This discovery enabled further research on the characteristics of the urine microbiomes of healthy people, as well as on the role of the urine microbiome in the pathogenesis of many urological diseases, including bladder diseases. The aim of this review is to summarize the current knowledge on the urinary microbiome in bladder diseases and to identify potential directions for further research.

The Influence of the Microbiome on Urological Malignancies: A Systematic Review

The microbiome, once considered peripheral, is emerging as a relevant player in the intricate web of factors contributing to cancer development and progression. These often overlooked microorganisms, in the context of urological malignancies, have been investigated primarily focusing on the gut microbiome, while exploration of urogenital microorganisms remains limited. Considering this, our systematic review delves into the complex role of these understudied actors in various neoplastic conditions, including prostate, bladder, kidney, penile, and testicular cancers. Our analysis found a total of 37 studies (prostate cancer 12, bladder cancer 20, kidney cancer 4, penile/testicular cancer 1), revealing distinct associations specific to each condition and hinting at potential therapeutic avenues and future biomarker discoveries. It becomes evident that further research is imperative to unravel the complexities of this domain and provide a more comprehensive understanding.

Development of a risk nomogram predicting urinary tract infection in patients with indwelling urinary catheter after radical surgery for cervical cancer

BACKGROUND

Cervical cancer (CC) patients receiving indwelling catheterization after radical hysterectomy (RH) are vulnerable to urinary tract infection (UTI). However, no model or method is available to predict the risk of UTIs. Therefore, our aim was to develop and verify a risk model to predict UTI for patients receiving indwelling catheterization after radical cervical cancer surgery (ICa-RCCS).

METHODS

We first collected clinical information of 380 patients receiving ICa-RCCS from January 2020 to December 2021 as a training cohort to develop the risk nomogram. UTI was then evaluated using 19 UTI predictor factors. The least absolute shrinkage and selection operator (LASSO) method was utilized for the extraction characteristics. Multivariable logistic regression analysis was then conducted to create the risk model for UTI prediction. The consistency coefficient and calibration curve were utilized to assess the model's fit accuracy. We performed bootstrapping with 1000 random samples for internal validation of the model, and decision curve analysis (DCA) for clinical application.

RESULTS

Predictors in the risk nomogram included indwelling catheterization duration, whether it is secondary indwelling catheterization, history of UTIs, age, and history of chemotherapy before surgery. The risk nomogram presented good discrimination and calibration (C-index: 0.810, 95% CI: 0.759-0.861). During interval validation, the model reached a high C-index up to 0.7930. DCA revealed the clinical utility of predictive model for UTI. Clinical benefit was initiated at the decision threshold≥3%.

CONCLUSION

We developed a novel UTI nomogram incorporating the age, history of chemotherapy before surgery, indwelling catheterization duration, whether it is secondary indwelling catheterization, and history of UTI to predict UTI risk for patients receiving ICa-RCCS.

LEVEL OF EVIDENCE

B: 3a.

Determinants of urinary tract infection in hospitalized patients with acute ischemic stroke

BACKGROUND

Stroke is a major cause of morbidity and mortality worldwide. Urinary tract infection (UTI) is a common post-acute ischemic stroke (AIS) complication. We assessed the incidence, determinant factors, infection characteristics, post-stroke complications, and outcomes of hospitalized AIS patients with UTI.

METHODS

This retrospective cohort study included AIS patients admitted within 7 days of stroke onset. The patients were divided into the UTI group and the non-UTI (control) group. Clinical data were collected and compared between the groups.

RESULTS

There were 342 AIS patients (31 with UTIs and 311 controls). The multivariate analysis showed that an initial National Institutes of Health Stroke Scale (NIHSS) score of ≥ 15 (odds ratio [OR] 5.00, 95% confidence interval [CI] 1.33-18.72) and Foley catheter retention (OR 14.10, 95% CI 3.25-61.28) were risk factors for UTI, whereas smoking (OR 0.08, 95% CI 0.01-0.50), an initial systolic blood pressure (SBP) of > 120 mmHg (OR 0.06, 95% CI 0.01-0.31), and statin use (OR 0.02, 95% CI 0.0006-0.42) were protective factors. Twenty cases (64.5%) were community-acquired and 11 cases (35.3%) were hospital-acquired. Ten patients (32.3%) had catheter-associated UTIs. The most common pathogen was Escherichia coli (13 patients, 41.9%). Post-stroke complications were significantly more common in the UTI group, including pneumonia, respiratory failure, sepsis, brain edema, seizure, symptomatic hemorrhagic transformation, congestive heart failure, atrial fibrillation with a rapid ventricular response, acute kidney injury, and hyponatremia. The median length of stay (LOS) in the UTI group was 12 days versus 3 days in the control group (p < 0.001). The median 3-month modified Rankin Scale score was higher (5 in UTI and 2 in control; p < 0.001) and the median 3-month Barthel Index was lower (0 in UTI and 100 in control; p < 0.001) in the UTI group than in the control group.

CONCLUSIONS

The risk factors for post-AIS UTI included severe stroke (NIHSS score ≥ 15) and urethral catheter indwelling. An initial SBP of > 120 mmHg and statin use were protective factors. The UTI group had significantly worse post-stroke complications, a longer LOS, and worse 3-month outcomes. Smoking was protective, which requires further investigation.

Risk factors for catheter-associated urinary tract infections following radical hysterectomy for cervical cancer

BACKGROUND

Radical hysterectomy is the mainstay of treatment for early-stage cervical cancer. Urinary tract dysfunction is one of the most common complications after radical hysterectomy, and prolonged catheterization has previously been defined as a significant risk factor for catheter-associated urinary tract infections.

OBJECTIVE

This study aimed to determine the rate of catheter-associated urinary tract infections after radical hysterectomy for cervical cancer, and to identify additional risk factors for developing catheter-associated urinary tract infections in this population.

STUDY DESIGN

We reviewed patients who underwent radical hysterectomy for cervical cancer from 2004 to 2020 after institutional review board approval. All patients were identified from institutional Gynecologic Oncology surgical and tumor databases. The inclusion criterion was radical hysterectomy for early-stage cervical cancer. Exclusion criteria included inadequate hospital follow-up, insufficient records of catheter use in the electronic medical record, urinary tract injury, and preoperative chemoradiation. Catheter-associated urinary tract infection was defined as an infection diagnosed in a catheterized patient or within 48 hours of catheter removal, with significant bacteriuria (>10³ cfu/mL) and symptoms or signs attributable to the urinary tract. Data analysis was performed using comparative analysis and univariate and multivariable logistic regression using Excel, GraphPad Prism, and IBM SPSS Statistics.

RESULTS

Of the 160 included patients, 12.5% developed catheter-associated urinary tract infections. In univariate analysis, catheter-associated urinary tract infection was significantly associated with current smoking history (odds ratio, 3.76; 95% confidence interval, 1.39-10.08), minimally invasive surgical approach (odds ratio, 5.24; 95% confidence interval, 1.91-16.87), estimated surgical blood loss >500 mL (odds ratio, 0.18; 95% confidence interval, 0.04-0.57), operative time >300 minutes (odds ratio, 2.92; 95% confidence interval, 1.07-9.36), and increased duration of catheterization (odds ratio, 18.46; 95% confidence interval, 3.67-336). After adjusting for interactions and controlling for potential confounders with multivariable analysis, current smoking history and catheterization for >7 days were identified as independent risk factors for development of catheter-associated urinary tract infections (adjusted odds ratio, 3.94; 95% confidence interval, 1.28-12.37; adjusted odds ratio, 19.49; 95% confidence interval, 2.78-427).

CONCLUSION

Preoperative smoking cessation interventions for current smokers should be implemented to decrease risk for postoperative complications, including catheter-associated urinary tract infections. In addition, catheter removal within 7 postoperative days should be encouraged in all women undergoing radical hysterectomy for early-stage cervical cancer in an effort to decrease infection risk.

Bacteria for Treatment: Microbiome in Bladder Cancer

The human body contains a variety of microbes. The distribution of microbes varies from organ to organ. Sequencing and bioinformatics techniques have revolutionized microbial research. Although previously considered to be sterile, the urinary bladder contains various microbes. Several studies have used urine and bladder tissues to reveal the microbiome of the urinary bladder. Lactic acid-producing bacteria, such as Bifidobacterium, Lactobacillus, and Lactococcus, are particularly beneficial for human health and are linked to bladder cancer. This review highlights the analysis protocols for microbiome research, the studies undertaken to date, and the microbes with therapeutic potential in bladder cancer.

Bladder Tissue Microbiome Composition in Patients of Bladder Cancer or Benign Prostatic Hyperplasia and Related Human Beta Defensin Levels

Balance between the microbiome associated with bladder mucosa and human beta defensin (HBD) levels in urine is a dynamic, sensitive and host-specific relationship. HBD1—possessing both antitumor and antibacterial activity—is produced constitutively, while the inducible production of antibacterial HBD2 and HBD3 is affected by bacteria. Elevated levels of HBD2 were shown to cause treatment failure in anticancer immunotherapy. Our aim was to assess the relationship between microbiome composition characteristic of tumor tissue, defensin expression and HBD levels measured in urine. Tissue samples for analyses were removed during transurethral resection from 55 bladder carcinoma and 12 prostatic hyperplasia patients. Microbiome analyses were carried out with 16S rRNS sequencing. Levels of HBD mRNA expression were measured with qPCR from the same samples, and urinary amounts of HBD1, 2 and 3 were detected with ELISA in these patients, in addition to 34 healthy volunteers. Mann–Whitney U test, Wilcoxon rank sum test (alpha diversity) and PERMANOVA analysis (beta diversity) were performed. Defensin-levels expressed in the tumor did not clearly determine the amount of defensin measurable in the urine. The antibacterial and antitumor defensin (HBD1) showed decreased levels in cancer patients, while others (HBD2 and 3) were considerably increased. Abundance of Staphylococcus, Corynebacterium and Oxyphotobacteria genera was significantly higher, the abundance of Faecalibacterium and Bacteroides genera were significantly lower in tumor samples compared to non-tumor samples. Bacteroides, Parabacteroides and Faecalibacterium abundance gradually decreased with the combined increase in HBD2 and HBD3. Higher Corynebacterium and Staphylococcus abundances were measured together with higher HBD2 and HBD3 urinary levels. Among other factors, defensins and microorganisms also affect the development, progression and treatment options for bladder cancer. To enhance the success of immunotherapies and to develop adjuvant antitumor therapies, it is important to gain insight into the interactions between defensins and the tumor-associated microbiome.

Regulatory mechanisms and potential medical applications of HNF1A-AS1 in cancers

Long noncoding RNAs (lncRNAs) are defined as a class of non-protein-coding RNAs that are longer than 200 nucleotides. Previous studies have shown that lncRNAs play a vital role in the progression of multiple diseases, which highlights their potential for medical applications. The lncRNA hepatocyte nuclear factor 1 homeobox A (HNF1A) antisense RNA 1 (HNF1A-AS1) is known to be abnormally expressed in multiple cancers. HNF1A-AS1 exerts its oncogenic roles through a variety of molecular mechanisms. Moreover, aberrant HNF1A-AS1 expression is associated with diverse clinical features in cancer patients. Therefore, HNF1A-AS1 is a promising biomarker for tumor diagnosis and prognosis and thus a potential candidate for tumor therapy. This review summarizes current studies on the role and the underlying mechanisms of HNF1A-AS1 various cancer types, including gastric cancer, liver cancer, glioma, lung cancer, colorectal cancer, breast cancer, bladder cancer, osteosarcoma, esophageal adenocarcinoma, hemangioma, oral squamous cell carcinoma, laryngeal squamous cell carcinoma, cervical cancer, as well as gastroenteropancreatic neuroendocrine neoplasms. We also describe the diagnostic, prognostic, and therapeutic value of HNF1A-AS1 for multiple cancer patients.

Bladder Microbiota Are Associated with Clinical Conditions That Extend beyond the Urinary Tract

Background. Since the discovery of the human urinary microbiota (UM), alterations in microbial community composition have been associated with various genitourinary conditions. The aim of this exploratory study was to examine possible associations of UM with clinical conditions beyond the urinary tract and to test some of the conclusions from previous studies on UM. Methods. Catheterised urine samples from 87 men were collected prior to endoscopic urological interventions under anaesthesia. The composition of the bacterial community in urine was characterized using the hypervariable V4 region of the 16S rRNA gene. Samples from 58 patients yielded a sufficient amount of bacterial DNA for analysis. Alpha diversity measures (number of operational taxonomic units, ACE, iChao2, Shannon and Simpson indices) were compared with the Kruskal–Wallis test. Beta diversity (differences in microbial community composition) was assessed using non-metric dimensional scaling in combination with the Prevalence in Microbiome Analysis algorithm. Results. Differences in bacterial richness and diversity were observed for the following variables: age, diabetes mellitus, dyslipidemia, smoking status and single-dose preoperative antibiotics. Differences in microbial community composition were observed in the presence of chronic kidney disease, lower urinary tract symptoms and antibiotic prophylaxis. Conclusions. UM appears to be associated with certain clinical conditions, including those unrelated to the urinary tract. Further investigation is needed before conclusions can be drawn for diagnostics and treatment.

Urogenital Microbiota:Potentially Important Determinant of PD-L1 Expression in Male Patients with Non-muscle Invasive Bladder Cancer

Background

Urogenital microbiota may be associated with the recurrence of bladder cancer, but the underlying mechanism remains unclear. The notion that microbiota can upregulate PD-L1 expression in certain epithelial tumors to promote immune escape has been demonstrated. Thus, we hypothesized that the urogenital microbiota may be involved in the recurrence and progression of non-muscle invasive bladder cancer (NMIBC) by upregulating the PD-L1 expression. To test this hypothesis, we investigated the relationship between urogenital microbial community and PD-L1 expression in male patients with NMIBC.

Results

16S rRNA gene sequencing was performed to analyse the composition of urogenital microbiota, and the expression of PD-L1 in cancerous tissues was detected by immunohistochemistry. The subjects (aged 43–79 years) were divided into PD-L1-positive group (Group P, n = 9) and PD-L1-negative group (Group N, n = 19) respectively based on their PD-L1 immunohistochemical results. No statistically significant differences were found in the demographic characteristics between group P and N. We observed that group P exhibited higher species richness (based on Observed species and Ace index, both P < 0.05). Furthermore, subgroup analysis showed that the increase in number of PD-L1 positive cells was accompanied by increased richness of urogenital microbiota. Significantly different composition of urogenital microbiota was found between group P and group N (based on weighted Unifrac and unweighted Unifrac distances metric, both P < 0.05). Enrichment of some bacterial genera (e.g., Leptotrichia, Roseomonas, and Propionibacterium) and decrease of some bacterial genera (e.g., Prevotella and Massilia) were observed in group P as compared with group N. These findings indicated that these genera may affect the expression of PD-L1 through some mechanisms to be studied.

Conclusion

Our study provided for the first time an overview of the association between urogenital microbiota and PD-L1 expression in male patients with NMIBC, indicating that urogenital microbiota was an important determinant of PD-L1 expression in male NMIBC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02407-8.