Since FOXP3 levels are decreased in patients with PV because of the abnormal expression of miR-338-3p, and FOXP3 is key to the role of Tregs cells in maintaining the immunological tolerance to self-antigens, this miRNA could play an essential role in the pathogenesis of the Tregs dysregulation observed in these patients (Reolid et al., 2021). This evidence concerns the gene FOXP3 and acquired polycythemia vera.