TP53 and lymphoma: We then collected more lymphoma tissues from Rps27l−/−;Trp53+/− mice at age of 4–6 months for Trp53 genotyping and found that the wild type Trp53 allele was deleted in 29 out of 30 (97%) lymphomas genotyped (Figure 8—figure supplement 1C,D), indicating that Rps27l disruption imposed the selection pressure against wild-type Trp53. We further measured the genome integrity of these lymphoma cells by metaphase chromosome spread and found a high degree of aneuploidy in up to 63% of total population (Figure 8E, Figure 8—figure supplement 1E).