A study recently published in Urologic Oncology found that the urinary microbiome is different from the microbiome found in bladder cancer tissue, demonstrating that urine might not provide an accurate picture of the tumor-associated microbiome in bladder cancer.
The word “microbiome” refers to the diversity of microorganisms found at a location in the body. Though the urinary tract was traditionally considered to be sterile, recent advancements have found it contains microbiota. Scientists have found a relationship between alterations in this urinary microbiome and various urological diseases, such as neurogenic bladder dysfunction and urgency urinary incontinence.
Investigators sought to better understand the link between microbiomes present in both the urine and the bladder in patients with bladder cancer. Specifically, they focused on patients who underwent one of two surgical procedures: transurethral resection of bladder tumor (TURBT) and radical cystectomy (RC). TURBT involves the removal of the cancer through the urethra, while RC involves the surgical removal of the bladder and surrounding structures.
Twenty-one patients were included in this study, with the median age being 72 years. Of the 21 patients, 11 underwent TURBT and 10 underwent RC. Nineteen of these patients (90%) had high-grade urothelial carcinoma.
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The microbiomes from urine samples and the bladder were analyzed. Researchers found that there were no significant differences in terms of alpha diversity indices. However, using the Bray Curtis for beta diversity, results showed significant dissimilarity. All these technical terms essentially mean one thing: “In this cohort, bladder-cancer tissue associated microbiome exhibited a distinct microbial signature when compared to urine,” the study’s authors wrote.
Scientists remain unclear if the urinary microbiome has anything to do with bladder cancer. A theory suggests that the urinary microbiome protects the urothelium — the lining of the urinary tract, including the bladder — against harmful foreign substances. Should scientists gain a better understanding of what bladder microbiomes do, future steps may include manipulating their composition to benefit the patient.
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