Mechanisms of the gut-lung axis in regulating lung metastasis of colorectal cancer and advances in traditional Chinese medicine intervention

Figure 1 A schematic diagram that shows the gutlung axis in the situation of colorectal cancer lung metastasis. The key essential elements are presented: Gut microbial flora (the dysbiosis which involves Fusobacterium nucleatum and enterotoxigenic Bacteroides fragilis), metabolic products (short-chain fatty acids, succinate), intestines barrier (gut leakage), exosomes (which carry microRNAs and circular RNAs), immunity cell movement (T helper 17, regulatory T), and the lung pre-metastatic niche. LPS: Lipopolysaccharide; ETBF: Enterotoxigenic Bacteroides fragilis; SCFAs: Short-chain fatty acids; Th17: T helper 17; Treg: Regulatory T.