Gut microbiota-derived metabolites, including short-chain fatty acids (SCFAs), long-chain fatty acids (LCFAs), and adenosine, act on bladder cancer-specific targets via receptor-mediated pathways or vagus nerve signaling, inducing changes in immune factors such as IL-6 and IL-8, which play critical roles in suppressing bladder cancer initiation and progression. The gene discussed is CXCL8; the disease is urinary bladder cancer.