The National Cancer Institute team has discovered how bacteria in the gut affects anti-tumor immune responses in the liver, a connection that could be used to find new therapies for liver cancer.

Tim Greten, M.D., of the NCI's Center for Cancer Research and the co-workers, investigated three different mouse models of liver cancer. They discovered that the mouse given the antibiotic vancomycin to exhaust their gut bacteria, had smaller liver tumors than control animals. The antibiotic also seemed to help to reduce metastasis.         

Further studies have shown, antibiotic aided to level-up the protein CXCL16 in endothelial cells which line the liver's capillaries. That procedure, in turn, to improve the quantity of natural killer (NK) T cells in the animals' livers, the build-up of NKT cells, led to a decrease in tumor growth.

"We wondered, why do mice treated with vancomycin have more CXCL16 production in these endothelial cells?" Greten mentioned in a press release. "That was censorious when we found that bile acids can control the expression of CXCL16 and discovered that if we treat mice with bile acids, we can actually change the number of NKT cells in the liver, and thereby the number of tumors in the liver."