Exploring the Possible Role of Endometriosis-Associated Dysbiosis in Endometrial Carcinogenesis

Background and Objectives: Endometriosis is associated with chronic inflammation, immune dysregulation, oestrogen-dependent growth, oxidative stress, altered steroid hormone metabolism, compromised epithelial barrier integrity, and the production of bioactive microbial metabolites. These interconnected alterations have been proposed to create, in principle, a permissive local microenvironment for malignant transformation. This narrative review examines whether endometriosis-associated dysregulation of the gut and reproductive tract microbiota may act as a hypothetical biological modulator linking these multi-axis changes to endometrial carcinogenesis, with attention to immunological, endocrine, metabolic, microbial–metabolite, oxidative, and barrier-related pathways. Material and Methods: We narratively integrated current evidence on gut and reproductive tract microbiota alterations relevant to endometrial homeostasis, with emphasis on the estrobolome, low-biomass uterine microbial communities, inflammatory and immune signaling, microbial metabolites, and pathways implicated in carcinogenesis. Results: Available data suggest that dysbiosis may influence endometrial carcinogenesis through interconnected endocrine, inflammatory, metabolic, and immune mechanisms. Attention has been given to loss of Lactobacillus dominance, enrichment of anaerobic and pro-inflammatory taxa, altered estrogen recirculation, progesterone resistance, Toll-like receptor activation, NF-κB/STAT3 signaling, COX-2/PGE2 activity, PI3K/AKT/mTOR pathway activation, oxidative stress, macrophage polarization, and impaired natural killer cell surveillance. These alterations may contribute to a permissive microenvironment characterized by persistent inflammation, defective immune control, and disrupted endometrial homeostasis. However, the current literature remains limited by small and heterogeneous cohorts, predominantly cross-sectional designs, contamination risk, and marked methodological variability, particularly in low-biomass uterine samples. Conclusions: Current evidence supports the view that microbiome dysregulation is a context-dependent biological modulator that intersects with endocrine, inflammatory, metabolic, immune, oxidative, and barrier-related pathways relevant to endometrial carcinogenesis. Microbiome dysbiosis should be regarded as a hypothetical contributory factor rather than as an established causal driver. Its near-term translational relevance appears greater for biomarker development and risk stratification than for immediate microbiome-directed therapy. Longitudinal, standardized, and functionally integrated studies are needed to clarify whether microbiome-associated signatures can be translated into clinically meaningful prevention and management strategies in endometrial cancer.