Correlation between urogenital microbiota and cancer: a review of mechanisms, clinical opportunities and limitations

The human urogenital tract, previously considered sterile, is now understood to be a complex microbial ecosystem with significant health implications. Dysbiosis of the urinary and genital microbiota contributes to carcinogenesis through multiple mechanisms, including chronic inflammation, the production of genotoxic metabolites, hormonal dysregulation, and immune modulation. Understanding this phenomenon could help us use it as a biomarker for cancer diagnosis. Despite previous studies identifying various microbial associations with urogenital cancers, the current review specifically aims to highlight the mechanistic interactions between microbial metabolites and the host immune response across different types of urogenital cancers, as well as their diagnostic potential and the challenges in their application to diagnosis and treatment. Across the reviewed studies on bladder, cervical, ovarian, endometrial, and prostate cancers, we noticed a consistent trend. There was a loss of protective bacteria, such as Lacbacillus , to Ruminococcaceae and, along with an increase in harmful species, including Fusobacterium , Campylobacter , Cupriavidus , Haemophilus , and Escherichia‑Shigella . From a diagnostic standpoint, specific microbial patterns in bladder cancer are associated with disease stage and recurrence risk. This suggests they might be useful as initial non-invasive markers for early detection and monitoring, pending future validation. For renal, prostate, and gynecological cancers, the imbalanced microbial profiles varied more widely among studies. This indicates that diagnostic tests might need to be tailored to specific cancer types. When examining treatment, we found that microbial patterns in bladder cancer were associated with patients’ responses to Bacillus Calmette‑Guérin (BCG) immunotherapy, for example, pre‑treatment enrichment of Aureispira in non‑responders and higher abundance of Bifidobacterium in responders. This means the makeup of the microbiota may be associated with treatment outcomes, although current evidence derives from small, single-cohort studies. Although the associations between microbial imbalance and immune response in other urogenital cancers were less consistent, these findings still suggest potential treatment options, such as restoring protective bacteria or targeting harmful ones to improve immunotherapy outcomes. Current evidence suggests that changes in the urogenital microbiota are closely linked to cancer development and may serve as non-invasive diagnostic markers. However, the lack of standardized methods has led to mostly descriptive findings, and we need more well-designed studies to confirm these microbial signatures across diverse populations and cancer types.