a, Accumulation of unphosphorylated β-catenin in blasts. Cytospin slides with thymic cells were stained with the monoclonal antibody 8E4, which recognizes unphosphorylated β-catenin. Top: representative fluorescent images. CP, chronic phase; BC, blast crisis. Scale bars, 25 μm. Bottom: representative confocal images. DAPI, 4′,6-diamidino-2-phenylindole. Original magnification ×100. b, Marked increase in unphosphorylated β-catenin levels in the LSC and blast populations. BM cells were pooled from two blast-crisis or WT littermates and were lineage (Lin)-depleted before FACS analysis. c, Decreased and delayed leukaemogenesis after ablation of one allele of Ctnnb1. Kaplan–Meier survival curves with Logbank statistical analysis (denoted on the curves) summarize leukaemia development in transplantation experiments. Blue line, PtenloxP/loxP;Ctnnb1loxP/+;VEC-Cre+; green line, PtenloxP/loxP;VEC-Cre+.