MICROBIOTA AND BLADDER CANCER

In France, bladder cancer (BC) is the fourth leading cause of cancer (14,000 new cases per year). It affects older men (\>60 years old) and smoking is the main identified risk factor (RF). The persistence of a high sex ratio despite the increase in smoking among women has led to research into other environmental RFs for BC, which may include the microbiota. Recently, the concept of urinary microbiota in asymptomatic patients has been accepted. Studies on the urinary microbiota have shown dysbiosis associated with certain urogenital pathologies. Thus, similar to certain dysbiosis of the colonic mucosa microbiota associated with CRC, it is possible that certain bacteria or viruses in the bladder tissue microbiota may be involved in bladder carcinogenesis. An epidemiological study conducted by our laboratory showed a prevalence of BC of 14% (7/50) in patients carrying the bacterium Actinotignum schaalii in their urine. While studies have analysed the urinary microbiota of patients with BC, those comparing the microbiota of cancerous bladder tissue with that of healthy tissue in patients with BC remain few in number, involve a limited number of patients, use uncontrolled sample collection, and have all used 16S rDNA-targeted metagenomics methods to study the composition of the microbiota. The authors show a difference in biodiversity between the microbiota of cancerous bladder tissue and that of healthy tissue. The team hopes to confirm these preliminary results with a multicentre study using a more comprehensive genomic method, global metagenomics. The microbiota of cancerous bladder tissue will be compared with that of healthy bladder tissue in the same patient to highlight any bacterial or viral dysbiosis associated with the cancerous area.