CXCL16 and hepatocellular carcinoma: In addition, the conversion of PBAs into SBAs mediated by gut microbiota can regulate the expression of CXCL16, which in turn regulates the accumulation of C-X-C chemokine receptor type 6+ (CXCR6+) NKT cells in the liver, thereby inducing liver-specific anti-tumor effects and inhibiting HCC progression [65].