Fig. 4. Heterozygous Trp53 missense mutations confer a competitive advantage over Trp53^+/− HSPCs upon sublethal gamma-irradiation.

(A) Schematic of the experimental workflow for hematopoietic competition assays in mixed chimeric mice to assess the relative competitive fitness of Trp53 genotypes upon sublethal gamma-irradiation. Trp53^+/+-CD45.1/2 recipient mice were engrafted with a 1:1 mixture of Trp53 genotypes from either CD45.1 or CD45.2 mice. Following hematopoietic reconstitution, mixed chimeric mice were sublethally gamma-irradiated (single dose of 2.5 Gy), and thereafter, peripheral blood (PB) chimerism was assessed by flow-cytometry every 4 weeks. (B-D) PB chimerism in mixed chimeric mice of the indicated genotypes in non-irradiated control mice (black squares) and mice treated with a single dose of 2.5 Gy gamma-irradiation (red squares). (experimental replicates n=2-3 per group, n=14-20 mice per group, symbols represent averages of individual mice across experimental replicates, error bars indicate s.e.m., * p<0.05, ** p<0.01, *** p<0.001, **** p<0.0001, Mann-Whitney test) (E) Schematic summary of the results obtained from hematopoietic competition assays depicting the relative competitive fitness of the indicated Trp53 genotypes towards sublethal DNA damage. (F) Kaplan-Meier analysis for event-free and (G) overall survival in AML patients according to TP53 mutational status (missense mutations, blue line or truncating mutations comprising frame-shift, nonsense, and splice mutation, red line, log-rank (Mantel-Cox) test).