Insights into the Interplay between the Urinary Microbiome and Bladder Cancer: A Comprehensive Review.

New insights in the urinary microbiome have led to a better understanding being built of the shifts in bacterial representations from health to disease; these hold promise as markers for diagnosis and therapeutic responses. Although several efforts have been made to identify a "core urinary microbiome", different fingerprints have been identified in men and women that shift with age. The main bacterial groups overall include Firmicutes , Actinobacteria , Fusobacteria , and Bacteroidetes . Although patients with bladder cancer have a microbiome that is similar to that of healthy individuals, differences have been observed at the species level with Fusobacterium nucleatum and Ralstonia , and at the genus level with Cutibacterium . Different bacterial representations may influence extracellular matrix composition, affecting tumor metastatic spreading and tumorigenic metalloproteinase expression. Furthermore, gene expression affecting targets of immune therapy, such as PD-L1, has been associated with changes in bacterial representations and therapeutic response to BCG. This comprehensive review aims to examine the influence of the urinary microbiome in bladder cancer.