Bladder Cancer and the Urinary Microbiome-New Insights and Future Directions: A Review

The presence of a microbiome in the urinary system has been established through recent advancements in technology and investigation of microbial communities in the human body. The study of the taxonomic and genomic ecology of microbial communities has been greatly improved by the use of metagenomics. The research in this area has expanded our understanding of microbial ecosystems and shows that the urinary tract contains over 100 species from over 50 genera, with Lactobacillus, Gardnerella, and Streptococcus being the most common. Previous studies have suggested that the microbiota in the urinary tract may play a role in carcinogenesis by causing chronic inflammation and genotoxicity, but more research is needed to reach a definite conclusion. This is a narrative review. We conducted a search for relevant publications by using the databases Medline/PubMed and Google Scholar. The search was based on keywords such as "urinary microbiome," "bladder cancer," "carcinogenesis," "urothelial carcinoma," and "next-generation sequencing." The retrieved publications were then reviewed to study the contribution of the urinary microbiome in the development of bladder cancer. The results have been categorized into four sections to enhance understanding of the urinary microbiome and to highlight its role in the emergence of bladder cancer through alterations in the immune response that involve T-cells and antibodies. The immune system and microbiome play crucial roles in maintaining health and preventing disease. Manipulating the immune system is a key aspect of various cancer treatments, and certain gut bacteria have been linked to positive responses to immunotherapies. However, the impact of these treatments on the urinary microbiome, and how diet and lifestyle affect it, are not well understood. Research in this area could have significant implications for improving bladder cancer treatment and patient outcomes.