CTLA4 and hepatocellular carcinoma: In particular, the expression of SLC1A5 correlates significantly with the prototypical immunotherapeutic gene biomarkers, including PD-1 and CTLA4. These correlations collectively indicate a potential role for SLC1A5 expression as a biomarker to predict a clinical benefit of using immune-checkpoint inhibitors to treat cancers, especially LGG and HCC.