Characterizing the composition and diversity of the vaginal microbiome in ovarian cancer

Vaginal dysbiosis, characterized by Lactobacillus depletion and anaerobic enrichment, may be relevant to ovarian cancer (OC) outcomes, yet comprehensive microbiome characterization in OC patients remains limited. Here, we characterize the prevalence and predictors of vaginal microbiome dysbiosis among racially diverse OC patients in the US.

We performed 16S rRNA gene sequencing on vaginal samples from 132 OC patients recruited as part of the population-based ORCHiD study. Latent Dirichlet Allocation (LDA), a computational topic modeling approach, was applied to identify distinct microbial community signatures representing co-occurring bacterial taxa.

Here, we show that Lactobacillus is detected in only 47.7% of patients. Topic modeling identifies seven distinct microbial signatures spanning Lactobacillus-dominated and anaerobe-enriched community types. Anaerobic bacterial enrichment (Peptoniphilus, Anaerococcus) increases significantly with age (approximately 35% per decade of life, FDR q = 0.019). Racial differences are observed, with non-Hispanic Black patients demonstrating a 5-fold higher prevalence of an Actinomycetaceae-classified amplicon sequence variant (ASV54) compared with non-Hispanic white patients (40.9% vs 8.2%, FDR q = 0.005), while Lactobacillus crispatus is detected only among non-Hispanic white patients (6.4% vs 0%) in this cohort.

These findings demonstrate a high burden of vaginal microbiome dysbiosis among OC patients and identify age- and race-associated microbial patterns that may be relevant to understanding disparities in OC outcomes.