Loss of one allele of Moz increases lymphoma-free survival by 3.9-fold in the Eμ-Myc model. (A) Typical features of an Eμ-Myc lymphoma. Arrows indicate markedly enlarged lymph nodes and spleen, which are characteristic of Eμ-Myc^T/+ lymphoma. (B) Kaplan-Meier survival curves comparing Moz^+/−; Eμ-Myc^T/+ and Moz^+/+; Eμ-Myc^T/+ mice. Shading represents the 95% confidence interval. (C) Depiction of the median, 25th, and 75th percentile survival periods of Moz^+/−; Eμ-Myc^T/+ and Moz^+/+; Eμ-Myc^T/+ mice. (D) Moz and Myc mRNA levels in pre–B-cells. Gene expression levels were standardized to housekeeping genes Hsp90ab1 and Gapdh, and expression in WT samples was designated as 1. (E) Quantification of tumor immunophenotypes. (F) Representative flow cytometry plots depicting pre-B, immature B, and mixed pre-B/immature B-cell lymphomas. (G) Analysis of p53 and p19^ARF status of tumor samples from Moz^+/−; Eμ-Myc^T/+ and Moz^+/+; Eμ-Myc^T/+ mice. High p53 expression is characteristic of most Trp53 mutations, as mutated p53 is no longer able to activate Mdm2, preventing the induction of p53 destruction (see schematic). Normally, high levels of p19^ARF are evident in Eμ-Myc transgenic cells; however, upon Arf deletion, p19^ARF protein is not detectable. Data above are presented as mean ± SEM. Asterisks indicate a statistically significant difference between Moz^+/− and WT, or between Moz^+/−; Eμ-Myc^T/+ and Moz^+/+; Eμ-Myc^T/+ mice at *P < .05 and ***P < .001.