NT5E and oral cavity squamous cell carcinoma: As shown in Supplemental Material, median CD73 expression level in tumor tissues was significantly higher than that in normal tissues in most kinds of cancers including bladder, brain, invasive lobular breast, esophageal, gastric, pancreatic cancer, rectal mucinous, renal cell, lung large cell, oral cavity squamous cell carcinoma, melanoma, and lung adenocarcinoma (P < 0.05) (Additional file 1: Figures S1, S2, S3, S5, S6, S7, S8, S11, S12, S13, S15, S17).