IDO1 and hepatocellular carcinoma: A negative correlation exists between the upregulated expression of lnc-Tim3 in HCC patients and the production of IFN-γ and IL-2 by tumor-infiltrating CD8+ T cells.356 Similarly, lnc-sox5 is significantly elevated in CRC, and lnc-sox5 knockout significantly promotes CD8+ T infiltration and cytotoxicity by inhibiting indoleamine 2, 3-dioxygenase 1 (IDO1) expression, thereby inhibiting CRC tumorigenicity.357