The dual roles of Prevotella in gastrointestinal tumorigenesis: from molecular mechanisms to therapeutic prospects.

Tumor microbiology is a prominent area of research that is reshaping cancer treatment paradigms. While most microbiological studies have focused on specific bacterial species such as Fusobacterium nucleatum, the genus Prevotella has emerged in recent years as a key research focus due to its notable functional duality in gastrointestinal tumorigenesis. The role of this genus is not unidirectional; specific strains of Prevotella have been associated with either pro-tumorigenic or anti-tumorigenic effects depending on the context. On one hand, pro-tumorigenic strains, exemplified by Prevotella intermedia, have been shown to correlate with malignant progression through various mechanisms, though direct causal evidence in humans remains limited. On the other hand, certain Prevotella strains may exert protective effects primarily through the production of short-chain fatty acids (SCFAs), particularly butyrate, as suggested by preclinical and correlational human studies. This functional duality is fundamentally shaped by strain-level heterogeneity, dietary patterns, microbial community context, and anatomical localization. Despite the critical importance of this genus in the gastrointestinal tract, a comprehensive synthesis of its strain-specific and context-dependent roles remains lacking. This narrative review is based on literature searched in PubMed and Web of Science up to March 2026 using keywords including "Prevotella", "gastrointestinal cancer", "short-chain fatty acids", and "gut microbiota". Additional references were identified from reference lists. No formal bias assessment was performed. Therefore, this review summarizes the current understanding of the underlying mechanisms of its dual roles-emphasizing where evidence is associative versus causal-and explores emerging translational strategies that leverage this duality for cancer prevention and therapy.