CXCR6 and liver cancer: Ma et al. found that altering gut bacteria in liver tumor-bearing mice cause an antitumor effect associated with increased hepatic CXCR6+ NKT cells, and in human primary liver cancer tissues, higher levels of the primary bile acid CDCA were linked to CXCL16 expression, the ligand for CXCR6, and there was an inverse relationship for secondary bile acid glycolithocholate (GLCA) [20].