DKK2 and colorectal cancer: This study is based on the significant difference in the abundance of Fusobacterium mortiferum between obese adenoma patients and obese non-adenoma populations, aiming to explore whether Fusobacterium mortiferum and its metabolic product 5-aminovaleric acid can promote the occurrence of colorectal cancer in obese populations by inhibiting KDM6B-mediated DKK2 demethylation and activating the Wnt/β-catenin pathway.