Microbiome Profiling in Bladder Cancer Patients Using the First-morning Urine Sample

Background: Several studies support the interplay between the urinary microbiome (ie, urobiome) and bladder cancer (BCa). Specific urinary bacteria may be responsible for chronic inflammation, which in turn promotes carcinogenesis. Different signatures of urobiome in BCa patients were identified depending on tumor type, geographical area, age, and sex. Objective: We explored the urobiome in BCa patients undergoing transurethral resection of bladder tumor (TURBT), to identify possible predictive biomarkers of cancer. Design setting and participants: The urobiome analysis was conducted in 48 patients (13 females) undergoing TURBT, of whom 30 with BCa (five females) and 18 with benign bladder tumor, analyzing bacterial 16S rRNA by next-generation sequencing in first-morning (FM) urine samples. Forty-three cancer-free individuals and 17 prostate cancer patients were used as controls. Outcome measurements and statistical analysis: First, we identified the better urine collection procedure to perform the urobiome analysis, comparing bacterial composition between catheterized (CAT) and FM urine samples in TURBT patients. Successively, we observed a specific urobiome in BCa patients rather than controls. A combined pipeline including the DESeq2 and linear discriminant analysis effect size tests was used to identify differential urinary taxa, strictly associated with BCa patients. Results and limitations: The bacterial composition of CAT and FM urine samples was comparable, so the latter was used for the following analyses. An increased abundance of Porphyromonas and Porphyromonas somerae was found in BCa patients compared with controls. This signature seems to be more related (p <0.05) to male BCa patients over 50 yr old. Owing to the low biomass of urinary microbiota, several samples were excluded from the study, reducing the number of BCa patients considered.