Molecular and Immunological Mechanisms Underlying the Anticancer Effects of Bifidobacterium

The genus Bifidobacterium, a prominent member of the human gut microbiota, has attracted increasing attention for its potential role in cancer prevention and treatment. Growing evidence suggests that Bifidobacterium species can modulate host immune responses, regulate inflammation, induce apoptosis, and inhibit tumour progression by modulating key oncogenic signalling pathways. This review highlights the molecular and immunological mechanisms underlying the anticancer effects of Bifidobacterium, with particular emphasis on its role in enhancing cancer immunotherapy. Recent studies have indicated that the abundance of Bifidobacterium is associated with improved responses to immune checkpoint inhibitors (ICIs) and other immunotherapeutic strategies, suggesting its potential as a microbiome-based adjuvant in cancer treatment. Moreover, advances in drug delivery approaches, including encapsulation technologies and genetically engineered Bifidobacterium strains, have improved their stability and tumour-targeting capabilities in preclinical models. Although promising results have been reported in experimental and animal studies, well-designed clinical trials are required to validate their therapeutic efficacy and safety in humans. Overall, this review summarizes the current evidence on the molecular pathways, immune modulation, and emerging therapeutic applications of Bifidobacterium, highlighting its potential as a novel microbiome-based strategy to improve cancer immunotherapy outcomes.