Gut Microbiota and Extraintestinal Cancers: Mechanistic Insights and Microbiome‐Targeted Interventions

have been shown to enhance therapeutic responses. Emerging evidence links gut microbiota to breast cancer via estrogen metabolism "estrobolome" to lung cancer through the gut-lung axis and modulation of ICI responses, to melanoma by shaping systemic T-cell function and immunotherapy outcomes, and to prostate cancer through androgen receptor signaling and microbial metabolite interactions. These findings underscore the systemic oncogenic and tumor-suppressive potential of microbial communities. Microbiome-targeted interventions, including fecal microbiota transplantation (FMT), defined live biotherapeutics, probiotics, prebiotics, dietary modulation, and postbiotic delivery, are being actively investigated to optimize cancer treatment. While early trials have demonstrated feasibility, variability between individuals and methodological challenges remain significant hurdles. Hence, understanding how gut microbes influence extraintestinal cancers could revolutionize diagnostics, risk prediction, and treatment strategies.