On Bacteroides Fragilis participation in vulvar carcinogenesis.

e17026 Background: The purpose of the study was to identify the rate of Bacteroides spp. infection in vulvar cancer tissues. Methods: FFPE samples of tumor and peritumoral area and healthy tissues of 44 patients with vulvar cancer, as well as frozen tumor tissues of 34 cervical cancer and 29 uterine cancer patients were studied. DNAs of Bacteroides spp. were detected by real-time PCR. Results: 18.75% of patients had stage I disease, 75.0% - stage II, 6.25% - stage III. The analysis of tumor histological type showed squamous cell carcinoma: G1 - 31.25%, G2 - 68.75%. B. fragilis were found in all vulvar tissues: tumor tissue – in 87.5%, perifocal area – in 76.9% and healthy tissue – in 71.4% of patients. Bacteroids of other groups were not found. For comparison, B. fragilis DNAs were detected in 20.7% in uterine cancer and in 15.4% in cervical cancer. DNA amount in samples was assessed by the Ct value. This index is inversely proportional to the DNA amount in the sample. Mean Ct level in tumor tissue was 23.2, in peritumoral area – 23.7, and in healthy tissue – 26.1; so, the amount of B. fragilis DNAs was similar in tumor and peritumoral area and was lower in healthy tissues. Differences in bacterial contamination of tumor tissue were found between vulvar cancer, cervical and uterine cancer. The amount of B. fragilis DNAs was maximal in vulvar cancer. We did not establish clear relationships between the rate of B. fragilis infection in tumor and the disease stage, tumor grade and the rate of metastasis. Conclusions: B .fragilis infection was found in tissues of the entire vulva; however, the infection rate and bacterial contamination level were higher in tumor tissue compared to the perifocal area and healthy tissue. Tumor tissues in vulvar cancer were infected more often than in uterine and cervical cancers. Bacterial contamination level in tumor tissue was higher in vulvar cancer than in uterine and cervical cancers which was undoubtedly significant in vulvar cancer pathogenesis.