Pten deletion accelerates CML development. (A) Structure of BCR-ABL-iCre-GFP retroviral construct. (B) BCR-ABL-GFP and BCR-ABL-iCre-GFP retrovirus transduced bone marrow cells from PTEN^fl/fl mice were cultured under the Whitlock-Witte conditions for 1 week. Protein lysates were analyzed by Western blotting with the antibodies indicated. iCre-induced deletion of the Pten gene resulted in the removal of Pten protein. (C) Kaplan-Meier-style survival curves for recipients of BCR-ABL-iCre-GFP–transduced bone marrow cells from wild-type (WT; n = 6) or PTEN^fl/fl (PTEN; n = 9) mice (P < .005). (D) The percentage of leukemia cells (GFP⁺Gr1⁺) in recipients of BCR-ABL-iCre-GFP–transduced bone marrow cells from Pten^fl/fl mice was greater than that in recipients of BCR-ABL-iCre-GFP–transduced bone marrow cells from wild-type mice. (E) The total number of leukemia cells (total white blood cell count × percentage of GFP⁺Gr1⁺ cells) in the peripheral blood of recipients of BCR-ABL-iCre-GFP–transduced bone marrow cells from PTEN^fl/fl mice (PTEN) was greater than that in recipients of BCR-ABL-iCre-GFP–transduced bone marrow cells from wild-type mice (WT). (F) Photomicrographs of hematoxylin and eosin-stained lung sections from recipients of bone marrow cells from PTEN-deficient CML mice (Pten^−/−) showed more severe infiltration of the lungs with myeloid leukemia cells than recipients of bone marrow cells from wild-type mice (WT) at day 14 after BMT. (G) Spleen weight of recipients of wild-type (WT) or Pten^fl/fl (Pten^−/−) bone marrow cells transduced with BCR-ABL-iCre-GFP retrovirus at day 14 after BMT (P = .028). (H) Gross appearance of the lungs and spleens showed severe lung hemorrhages and splenomegaly in recipients of BCR-ABL-iCre-GFP–transduced bone marrow cells from PTEN^fl/fl CML mice (Pten^−/−) than in recipients of the transduced wild-type (WT) bone marrow cells.