MSI analysis was performed as previously described.15 (link)TP53 mutation status was assessed in all 401 samples by sequencing the entire coding region (exons 2–11), as well as the first ten and last 10 nucleotides of each intron. Sequencing was done by Sanger sequencing technology using BigDye Terminator V.1.1 Cycle Sequencing Kit (Applied Biosystems) according to the manufacturer’s procedure. The samples were run on the 3730 DNA Analyzer (Applied Biosystems). All electropherograms were scored manually and independently by two of the authors, assisted by the SeqScape V.2.5 and Sequencing Analysis V.5.3.1 software (both Applied Biosystems). All mutations were resequenced for validation. Splice mutations were defined as any mutation affecting any of the first or the last 10 nucleotides of an intron, based on the finding that intron mutations outside the invariant AG and GT dinucleotides in the consensus splice acceptor and splice donor site, respectively, may lead to mis-splicing.24 (link) Tumours harbouring only synonymous mutations were classified as TP53 wild type (wt) in survival analysis. Mutation analyses had previously been performed for KRAS (exon 2: codons 12 and 13)14 (link) and BRAF (codon 600)25 (link) in all 401 samples. KRAS exon 3 codon 61 was analysed in a subset of samples (n=127).