P21 is upregulated in β-thalassemia erythroid cells. (A) qRT-PCR expression analysis of P21 in TER119⁺ (GI-GIV) cells. (B) Immunoblotting of P21 protein expression in WT, Foxo3^−/−, and Hbb^th3/+ TER119⁺ erythroblasts. Results are shown as mean ± SD; ∗P < .05 (n = 3 mice). (C) Immunoblot analysis of P21 expression in erythroblasts derived from healthy donors and CD34⁺ cells from patients with β-thalassemic. (D) Quantification of data shown in panel C.