CXCR6 and hepatocellular carcinoma: In addition, there are other GPCRs and ligands that may recruit Tregs, such as CCR5/CCL5 in colorectal cancer (CRC) and pancreatic cancer [104, 106], CCR6/CCL20 in HCC and breast cancer [108, 110], and CCR10/CCL28 in ovarian cancer [35], while CXCR3 and CXCR6 are expressed by Tregs infiltrating renal cell carcinoma [107].