Urinary bladder microbiome identification protocol with proteomics in bladder cancer patients and review of the literature

Abstract

Urine was conventionally thought to be sterile. However, recent evidence about the presence of microorganisms residing the urinary tract has led to an emerging field of investigation about the potential role of urinary microbiome in the pathogenesis of urinary bladder cancer. Urinary microbiota refers to the different microbe populations present in the urinary tract while a variety of genetic, environmental, and experimental parameters have been investigated as predisposing factors of microbial composition. Different methods of urine collection as well as experimental methodology on microbiome's characterization consist of well-defined factors that may alter the microbial composition. Few preliminary data have been reported so far implicating microorganisms as causative and prognostic factors of bladder tumorigenesis, examining mostly midstream-voided urine samples while the most commonly used analyzing technique was 16S rRNA sequencing method. In the present study, a protocol of microbiome identification using proteomics is reported analyzing differences in microbial composition between bladder cancer patients and healthy controls while a review of the current evidence is presented. To the best of our knowledge, proteomics has not been described as a possible method of microbiome characterization before.