Analysis of endometrial lavage microbiota reveals an increased relative abundance of the plastic-degrading bacteria Bacillus pseudofirmus and Stenotrophomonas rhizophila in women with endometrial cancer/endometrial hyperplasia

Abstract

Background: Endometrial cancer (EC) incidence rates are rapidly growing in several countries, but the underlying pathogenesis has not been completely elucidated. We undertook this study to compare the microbiota composition of endometrial lavage specimens obtained from Taiwanese patients with endometrial hyperplasia (EH) and EC, respectively versus women with benign uterine conditions.Methods: Endometrial lavage bacterial microbiota of 32 Taiwanese women who had undergone office hysteroscopy was characterized by 16S rRNA V3−V4 gene sequence analysis. Patients with either a newly diagnosed or known history of EH/EC (n = 24) and control women with benign uterine lesions (n = 8) were compared in terms of richness, diversity, and composition of endometrial lavage microbiota. Validation was performed using real-time QPCR (EH/EC, n = 46; control, n = 13). Microbiota datasets from Human Microbiome Project and the Integrative Human Microbiome Project were retrieved and compared.Results: At the species level, Bacillus pseudofirmus and Stenotrophomonas rhizophila – two plastic-degrading bacteria – were overrepresented in endometrial lavage specimens sampled from patients with EH/EC. The functional profiles of endometrial lavage microbiota differed between patients with EH/EC and control women, being associated with fatty acid and amino acid metabolism. A decrease in Lactobacillus was observed in EH/EC when compared to microbiota of cervix and vagina of healthy individuals. Conclusions: The plastic-degrading bacteria Bacillus pseudofirmus and Stenotrophomonas rhizophila may be a microbial signature of endometrial carcinogenesis in Taiwan, suggesting that patients with EH/EC may have increased exposure to environmental pollutants.