NT5E and cancer: Currently, they are undergoing clinical trials against malignant tumors based on their ability to directly inhibit the nucleotidase activity of CD73.[15, 48] As a result of minimal overall clinical efficacy, several trials (e.g., NCT03954704 and NCT04262388 in clinicaltrials.gov) involving CD73 blocking antibodies or small molecule inhibitors for advanced solid tumors have been discontinued.