SOCS1 cooperates with FLT3-ITD–induced disease in a murine bone marrow transplant model. (A) Kaplan-Meyer plot displays the survival after transplantation. All mice that received transplants of control or SOCS1-transduced bone marrow survived the 120 days of follow up. All animals from FLT3-ITD and SOCS1-T2A-FLT3-ITD died before the end of the experiment (120 days). Open circles/triangles represent ALL phenotype, filled circles/triangles represent MPD phenotype, and half-filled circles/triangles represent both events. (B) Representative microphotographs of spleens at the time of death. Spleens from control and SOCS1 mice (from 120 days after transplantation) or from FLT3-ITD and SOCS1-T2A-FLT3-ITD moribund mice indicate normal and enlarged spleens, respectively. (C-D) Analysis of spleen weight (C) and liver weight (D) at death or at the end of experiment (120 days). The mice that received FLT3-ITD and SOCS1-T2A-FLT3-ITD transplants suffered from splenomegaly compared with controls (C). In addition, mice transplanted with SOCS1-T2A-FLT3-ITD/MPD suffered from significantly increased hepatomegaly, compared with FLT3-ITD/MPD (D; * P < .05).