No Bacterial Biomass Detected in Tissue From Patients With Ovarian Cancer and Serous Tubal Intraepithelial Carcinomas Using 16S rDNA Sequencing

The ovarian oncobiome is subject to increasing scientific focus, but a potential link between bacterial dysbiosis and ovarian carcinogenesis remains controversial. Our primary aim was to characterize the bacterial microbiota in epithelial ovarian cancer samples. Secondarily, we aimed to compare results from the bacterial microbiota in formalin-fixed, paraffin-embedded ovarian tissue samples from 194 patients with epithelial ovarian cancer, fallopian tube tissue samples from 16 patients with serous tubal intraepithelial carcinomas and in benign fallopian tube tissue samples from 25 patients. Bacterial abundance was investigated by means of 16S rDNA Next Generation Sequencing. The 16S rDNA sequencing run produced a very low number of bacterial reads. Only seven samples displayed bacterial reads above 5000. Validation of detected bacterial reads by qPCR was negative and indicative of results being background amplification. Our results indicate no amount of bacterial biomass in the ovarian cancer, benign fallopian tube and in the samples with serous tubal intraepithelial carcinomas. The findings underline the importance of validating results from bacterial microbiota studies with additional technical assays before any conclusion may be drawn.