In fact, both MSI+ cancers contained three detectable, pathogenic p53 mutations (p.Arg158His/p.Thr102fs/p.Pro72fs in #18 and p.Arg267Trp/p.Pro191delCTC/p.Arg273Cys in #30) and the sequencing of additional FFPE tumour regions showed that some of these changes were spatially heterogeneous (Fig. 3). The gene discussed is TP53; the disease is neoplasm.