Impact of deletion of both alleles of Mcl-1 selectively in T-lymphoid cells on thymic lymphoma development in p53^−/− mice. (A) Tumor-free survival of p53^−/−;Lck-Cre (n = 26) and p53^−/−;Lck-Cre;Mcl-1^fl/fl mice (n = 17; log-rank Mantel-Cox test, P = .8292). (B) Flow cytometric analysis of Mcl-1^fl recombination in primary thymic lymphoma samples from p53^−/−;Lck-Cre (negative control) and p53^−/−;Lck-Cre;Mcl-1^fl/fl mice by immunofluorescent staining for the human CD4 (hCD4) reporter. (C) Incidence in % of thymic lymphoma, splenomegaly, sarcoma, or other pathologies in cohorts of p53^−/−;Lck-Cre (n = 26) and p53^−/−;Lck-Cre;Mcl-1^fl/fl mice (n = 17). (D) Analysis of the proteins indicated by western blotting of primary thymic lymphoma samples from mice of the indicated genotypes (representative of 6-10 samples each). Probing for HSP70 was used as a loading control. The numbers below western blots indicate the tumor samples also tested in B. Lanes 1 to 6 are the same image shown in Figure 3D and are presented here for comparison.