Metabolic Biosynthesis Pathways Identified from Fecal Microbiome Associated with Prostate Cancer

The impact of microbiome in urological diseases: a systematic review

OBJECTIVE

The term microbiome is used to signify the ecological community of commensal, symbiotic, and pathogenic microorganisms that share our body space, in which there were increasing evidences to suggest that they might have potential roles in various medical conditions. While the study of microbiome in the urinary system is not as robust as the systems included in the Human Microbiome Project, there are still evidences in the literature showing that microbiome may have a role in urological diseases. Therefore, we would like to perform a systematic review on the topic and summarize the available evidence on the impact of microbiome on urological diseases.

METHODOLOGY

This review was performed according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. After screening 589 abstracts and including additional studies (such as references from review papers), 76 studies were included for review and discussion.

RESULTS

Studies had suggested that there were correlations of microbiome of different body cavities (e.g., fecal, urinary and seminal fluid) with urological diseases. Also, different diseases would have different microbiome profile in different body cavities. Unfortunately, the studies on the association of microbiome and urological diseases were still either weak or inconsistent.

CONCLUSION

Studies suggested that there might be some relationship between microbiome and various urological diseases. However, further large-scale studies with control of confounding factors should be performed under a standardized methodology in order to have better understanding of the relationship. Also, more standardized reporting protocol for microbiome studies should be considered for better communications in future studies.

The Microbiome and Genitourinary Cancer: A Collaborative Review

CONTEXT

The recent discovery of the existence of a human genitourinary microbiome has led to the investigation of its role in mediating the pathogenesis of genitourinary malignancies, including bladder, kidney, and prostate cancers. Furthermore, although it is largely recognized that members of the gastrointestinal microbiota are actively involved in drug metabolism, new studies demonstrate additional roles and the potential necessity of the gastrointestinal microbiota in dictating cancer treatment response.

OBJECTIVE

To summarize the current evidence of a mechanistic role for the genitourinary and gastrointestinal microbiome in genitourinary cancer initiation and treatment response.

EVIDENCE ACQUISITION

We conducted a literature search up to October 2018. Search terms included microbiome, microbiota, urinary microbiome, bladder cancer, urothelial carcinoma, renal cell carcinoma, kidney cancer, testicular cancer, and prostate cancer.

EVIDENCE SYNTHESIS

There is preliminary evidence to implicate the members of the genitourinary microbiota as causative factors or cofactors in genitourinary malignancy. Likewise, the current evidence for gastrointestinal microbes in dictating cancer treatment response is mainly correlative; however, we provide examples where therapeutic agents used for the treatment of genitourinary cancers are affected by the human-associated microbiota, or vice versa. Clinical trials, such as fecal microbiota transplant to increase the efficacy of immunotherapy, are currently underway.

CONCLUSIONS

The role of the microbiome in genitourinary cancer is an emerging field that merits further studies. Translating microbiome research into clinical action will require incorporation of microbiome surveillance into ongoing and future clinical trials as well as expansion of studies to include metagenomic sequencing and metabolomics.

PATIENT SUMMARY

This review covers recent evidence that microbial populations that reside in the genitourinary tract-and were previously not known to exist-may influence the development of genitourinary malignancies including bladder, kidney, and prostate cancers. Furthermore, microbial populations that exist at sites outside of the genitourinary tract, such as those that reside in our gut, may influence cancer development and/or treatment response.

The Human Microbiota and Prostate Cancer: Friend or Foe?

The human microbiome is gaining increasing attention in the medical community, as knowledge on its role not only in health but also in disease development and response to therapies is expanding. Furthermore, the connection between the microbiota and cancer, especially the link between the gut microbiota and gastrointestinal tumors, is becoming clearer. The interaction between the microbiota and the response to chemotherapies and, more recently, to immunotherapy has been widely studied, and a connection between a peculiar type of microbiota and a better response to these therapies and a different incidence in toxicities has been hypothesized. As knowledge on the gut microbiota increases, interest in the residing microbial population in other systems of our body is also increasing. Consequently, the urinary microbiota is under evaluation for its possible implications in genitourinary diseases, including cancer. Prostate cancer is the most common cancer in the male population; thus, research regarding its etiology and possible factors correlated to disease progression or the response to specific therapies is thriving. This review has the purpose to recollect the current knowledge on the relationship between the human microbiota and prostate cancer.