NT5E and neoplasm: In the malignant tissue, where CD73 is already upregulated or induced by radiation, purinergic adenosine production leads to an immunosuppressive adenosine “halo” around the tumor that mediates immune escape as described above and in other recent reviews (Yang et al., 2021; Allard et al., 2023; Bach et al., 2023; Xia et al., 2023).