CCL4 and neoplasm: Mechanistically, fecal microbiota transplantation (FMT) of CRC bearers support tumor development by increasing the expression of pro-tumorigenic cytokines (e.g., IL-17A, IL-22, and IL-23), inflammatory chemokines (e.g., CCL-1, CCL-2, CCL-3, CCL-4, CXCL-12), and genes involved in the regulation of cell cycle, stemness, apoptosis, angiogenesis, tumor invasiveness, and metastasis [92].