ADA2 (Figure 5B), in most cancers, positively correlated with LGALS9, CD80, CTLA4, LAG3, TNFRSF9, PDCD1LG2, CD274, IDO1, TNFSF14, CD244, CD200R1, CD28, BTLA, PDCD1, CD40LG, ICOS, LAIR1, HAVCR2, CD86, CD48, CD27, and TIGIT. Moreover, ADA2 negatively correlated with CD276, TNFSF9, and VTCN1 in most cancers. This evidence concerns the gene BTLA and cancer.