Taxonomy, carcinogenic mechanisms, and advanced molecular diagnosis of Fusobacterium nucleatum in colorectal cancer: from bench to clinical practice.

Fusobacterium nucleatum (Fn) is recognized as a novel oncogenic organism closely correlated with colorectal cancer (CRC). Fn can induce gut dysbiosis and promote tumorigenesis through various mechanisms, including activation of oncogenic signaling, modulation of the immune microenvironment, metabolic reprogramming, and epigenetic regulation. Although recent technological breakthroughs have yielded high-resolution Fn detection indicators, clinical translation remains compromised by subspecies heterogeneity, emerging taxonomic updates, and non-standardization of diagnostic platforms. This review integrates recent developments regarding Fn pathogenic mechanisms and taxonomic identification in CRC, including genetic heterogeneity analysis at the species and subspecies levels, elucidation of multi-dimensional oncogenic molecular mechanisms, and application of high-resolution detection technologies. Special focus is placed on advancing these findings toward early noninvasive diagnostic markers. Additionally, we discuss the limitations of current studies, technical bottlenecks, and potential directions for future research to pave the way for standardized clinical screening.C.