TP53 and lymphoma: While AneuFinder analysis revealed that few cells were aneuploid at 10 weeks, the karyotypes observed in the enlarged thymuses harvested from 13- and 14-week-old Mps1; p53; Lck-Cre mice were already very similar to those observed in endpoint T-ALLs (compare Additional file 9: Figure S6b, c to Fig. 3d–g) indicating that selection for the frequently gained chromosomes 4, 9, 14 and 15 occurs early in lymphoma development.