CXCL12 and neoplasm: Upregulation of immune checkpoint proteins, such as PD-1, CTLA-4, and T-cell immunoglobulin mucin-3 (TIM-3), and of transcripts IL8 and CXCL12, concomitant with downregulation of granzyme B and perforin in tumor MAIT cells, indicates that MAIT cells are exhausted and pro-tumor in HCC [31].