MiR-125b induces tumorigenesis in pre-B cells. (A) MG and MG-125b were bled 12 weeks after bone marrow reconstitution. The figure represents the percent of B cells (CD19⁺) within the GFP⁺ gated population in the peripheral blood of these mice (at least 3 mice per group). P value was calculated by Student t test. (B) GFP⁺CD19⁺ B cells were sorted from MG-125b mice 4 to 6 months after bone marrow reconstitution. CD19⁺ B cells (35-52K) were transplanted into sublethally irradiated mice. The figure shows the flow cytometric analysis of the secondary recipient mice (bone marrow) 6 weeks after transplantation. Representative of 8 mice. (C) The figure shows the survival of curve of the secondary recipient mice transplanted with GFP⁺CD19⁺ cells from MG-125b mice (8 mice) or total BMCs from MG mice (6 mice). (D) Wright stain was performed from the blood of recipient mice injected with miR-125b–overexpressing CD19⁺ cells. The dark purple cells represent leukocytes. The smaller cells with central pallor are red blood cells. (E) Some recipients of miR-125b–overexpressing CD19⁺ cells develop lymphomas. Lymphomas shown at the superficial cervical (top blue arrow) and inguinal lymph node sites (side blue arrow). The normal mouse shown is a healthy C57bl/6 mouse. (F) Left panel, The spleen weight of the recipient mice transplanted with GFP⁺CD19⁺ cells (denoted as “miR-125b CD19⁺”) from MG-125b mice or total BMCs from MG animals were obtained 4 to 6 months after transplantation. Six mice per group. Right panel, Representative images of spleens harvested from normal C57bl/6 control and miR-125b CD19 transplanted mice 6 months posttransplant. (G) MiR-125b induces pre-B-cell cancer. Sorted GFP⁺CD19⁺ cells (10K) harvested from mice reconstituted with miR-125b–overexpressing EμMT BMCs were injected into sublethally irradiated secondary C57bl/6 recipients. Bone marrow of the secondary recipient harvested when the mice became moribund, and figure shows flow cytometric plot of the leukocyte population of the bone marrow. (H) Spleen weights of the secondary recipients described in panel H are shown (4 mice). The controls signify spleen weight from secondary recipients injected with cells from MG reconstituted mice (8 mice). P value was calculated by Student t test.