Lymphoblastic lymphoma in Stat5b TG mice. (A) CD4/CD8 profiles in Stat5b TG mice with and without lymphoma are compared with AKR mice with and without lymphoma and a WT control. Numbers indicate the percentage of cells in each quadrant, and total cellularity is indicated above each dot plot. (B) sCD3 expression versus FSC profiles reveals a characteristic pattern in the mice with lymphoma. (C) sTCRβ staining gated on CD8⁺ cells (CD8 SP and CD4/CD8 DP) is consistent with a T-cell origin of these lymphomas. Numbers indicate the mean fluorescence intensity (MFI) for the CD8⁺ (SP + DP) populations as well as the percentage within the gated region.