NOTCH1 and neoplasm: In support of this idea, DAOY-NERT2HIF2α−/− cells exhibited higher HIF1α protein levels under hypoxic conditions (Fig. 5h) and treatment of the DAOY-NERT2HIF2α−/− cells with the HIF1α inhibitor KC7F2 reduced tumor growth both under control and Notch1 ICD-activated conditions (Fig. 5i).