CTNNB1 and neoplasm: First, genetically homogeneous tumours with no clonal substructure, which acquire events at initiation (e.g. CTNNB1 mutation and chromosome 6 loss in MBWNT) followed by expansion of a single clone (i.e. no evolution); such trajectories were only observed in favourable-risk disease groups examined (e.g. MBWNT, Infant MBSHH).