TIGIT and cancer: In addition, the expression levels of multiple immune checkpoint proteins, including CTLA4, HAVCR2, PDCD1, TIGIT, CD27, and LAG3, were higher in the exhausted CD8+ T-cell subgroup with high PRKAA2 expression (Fig. 6E-G), implying that the functional exhaustion of CD8+ T cells may be a potential mechanism for PRKAA2-mediated cancer cell immune evasion.