CD73 expression within the tumor microenvironment has been studied as a prognostic biomarker for clinical outcomes in several tumor types, including breast cancer, lung cancer, ovarian cancer, kidney cancer, gastric cancer, prostate cancer, urothelial cancer, uterine cancer, melanoma, and head and neck cancers (Table 1) [2, 54–64, 66]. This evidence concerns the gene NT5E and lung cancer.