Low doses of RG7112 and Peg-IFNα 2a increase p53 activity. Normal (n = 5) and PV (n = 6) CD34⁺ cells were treated with 200 nM of RG7112 or 200 ng/mL of Peg-IFNα 2a alone or in combination. (A) Results of flow cytometric analysis of CD34⁺/p21⁺ cells in normal and PV CD34⁺ cells. (B) The fold change of numbers of CD34⁺/p21⁺ cells in normal and PV CD34⁺ cells after drug treatment. (C) Results of flow cytometric analysis of CD34⁺/PUMA⁺ cells after drug treatment of normal and PV CD34⁺ cells. (D) The fold change of CD34⁺/PUMA⁺ cell numbers after drug treatment of normal and PV CD34⁺ cells. (E) Flow cytometric analysis of CD34⁺/Bax⁺ cells after drug treatment of normal and PV CD34⁺ cells. (F) The fold change of numbers of CD34⁺/Bax⁺ cells after treatment of normal and PV CD34⁺ cells.