Overexpression of HMGA2 promotes hematopoiesis and causes extramedullary erythropoiesis in ΔHmga2 mice. (A) Increased BM cell counts in ΔHmga2 mice (n = 20) compared with WT mice (n = 18), and enlarged spleens (B) in ΔHmga2 mice (n = 8) compared with WT mice (n = 7). Representative examples are shown. (C) H&E stains of BM and spleen demonstrated an increased number of megakaryocytes in BM (left) and expanded red pulp in spleen (right) in ΔHmga2 mice. Representative photographs are shown. (D) Flow cytometry using lineage-specific markers, Gr1 (myeloid), Ter119 (erythroid), TCR (T cell), and B220 (B cell), showed an increased proportion of Ter119⁺ cells in BM and spleen (n = 3 in each experiment). *P < .05.