In conclusion, the inhibitory function of Notch1 inactivation on Th17 cells is definite in PV and results in the reversal of an imbalanced ratio of Th17/Treg and their specific transcription factor RORγt/Foxp3, which provides novel insights into the potential therapeutic target of Notch signaling for PV. The gene discussed is FOXP3; the disease is acquired polycythemia vera.