CTNNB1 and neoplasm: In addition, 9/19 patients harboured POLE mutations, or were annotated as ‘ultramutated' (tumours with more mutations than Q3+IQR × 4.5, where Q3 is the third quartile of mutation counts across a corresponding tumour type, and IQR is the interquartile range, as defined in syn1729383), suggesting that the CTNNB1 mutations were inconsequential passenger mutations (Supplementary Fig. 30, CTNNB1 P(F) distribution).