Suolistomikrobisto ja eturauhassyöpä

Abstract

Background: Although prostate cancer (PCa) is the most common cancer in men in Western countries, there is significant variability in geographical incidence. This might result from genetic factors, discrepancies in screening policies or differences in lifestyle. Gut microbiota has been recently associated with cancer progression, but its role in PCa is unclear. Objective: Characterization of the gut microbiota and its functions associated with PCa. Design, Setting and Participants: In a prospective multicenter clinical trial (NCT02241122), the gut microbiota profiles of 181 men with a clinical suspicion of PCa were assessed utilizing 16S rRNA sequencing. Outcome measurements and statistical analysis: Sequences were assigned to operational taxonomic units, differential abundance analysis, α- and β-diversities, and predictive functional analyses were performed. Plasma steroid hormone levels correspondence to the predicted microbiota steroid hormone biosynthesis profiles were investigated. Results and limitations: 181/364 patients were analyzed of which 60% were diagnosed with PCa. Microbiota composition and diversity was significantly different in PCa, partially affected by Prevotella 9, the most abundant genus of the cohort and significantly higher in PCa patients. Predictive functional analyses revealed higher 5-α-reductase, copper absorption, and retinol metabolism in the PCa associated microbiome. Plasma testosterone was associated negatively with the predicted microbial 5-α-reductase level. Conclusions: Gut microbiota of the PCa patients differed significantly compared to benign subjects. Microbial 5-α-reductase, copper absorption and retinol metabolism are potential mechanisms of action. These findings support the observed association of lifestyle, geography, and PCa incidence. Patient summary: In this report we found that several microbes and potential functions of the gut microbiota are altered in prostate cancer compared to benign cases. These findings suggest that gut microbiota could be the link between environmental factors and prostate cancer.