Tumor development in p53-null mice expressing VAV1 mutants. (A) OS of mice of indicated genotypes. (B) Macroscopic analysis of representative thymuses (i) at 12 weeks of age and spleens (ii) at 24 weeks of age from mice of indicated genotypes. (C) Representative data of chest (top) and abdominal (bottom) computed tomography scans, performed on p53^−/− V-Fus mice at 16 weeks (top) and 24 weeks (bottom) of age. WT mice served as controls. Arrows indicate a thymic tumor (Thy), swollen lymph node (Ly) and enlarged spleen (Sp), respectively. (D) Subtypes of tumors found in mice of indicated genotypes (p53^−/− V-Del, n = 21; p53^−/− V-Fus, n = 23; p53^−/−, n = 16). Immature T-cell neoplasms (T-lymphoblastic lymphomas [T-LBL]) are shown in blue; mature T-cell neoplasms (lymphoma [Lym]) in orange; and nonhematological malignancies in gray. (E) Cell-surface immunophenotypes of CD4 and CD8 cells from T-LBL or Lym from mice of indicated genotypes. (F) Representative flow cytometric data of CD4 and CD8, and CD24 and mTCR_β as indicators of cell-maturation status, and PD-1 and ICOS, indicating cell-activation status for thymocytes from p53^−/− V-Fus and p53^−/− mice harboring T-LBL plus WT mice (i) and splenocytes from p53^−/− V-Del and p53^−/− V-Fus mice harboring Lym plus WT mice (ii). (G) Representative flow cytometric data to show naive-like (CD4⁺CD62L⁺CD44⁻) and memory-like (CD4⁺CD62L⁻CD44⁺) phenotypes for splenocytes from p53^−/− V-Del and p53^−/− V-Fus mice harboring Lym plus WT mice. DN, double negative; DP, double positive; SP, single positive.