CXCL12 and malignant colon neoplasm: Increasing the content of SCFAs such as propionic acid and butyric acid in colon cancer cells, mediating the intestinal-derived SDF-1/CXCR 4 signaling pathway to repair the integrity of the intestinal barrier, decreasing the expression of Cyclin D1 and C-myc, and inhibiting tumor growth and metastasis.