CXCL9 and liver cancer: Regardless of whether HUVEC enhanced or reduced CXCL9 secretion when directly co-cultured with CD133+Hep-3B or CD133+PLC/PRF/5 respectively, CXCL9 secretion in the supernatants of the direct co- culture groups was still upregulated, which suggested that CXCL9 was mainly secreted by direct co-cultured CD133+ liver cancer cells.