Tumour DNA of 47 microsatellite stable CRCs was screened for somatic MIA3 mutations (Supplementary Table 3 ). Paired tumour-normal DNA samples of MIA3 p.Asp1432Glu carriers (68-1 and both carriers identified with screening) were screened for second hits in the MIA3 gene. Sequencing was performed with a custom multiplex PCR on the Ion Torrent Personal Genome Machine sequencer (Life Technologies, Grand Island, NY, USA) as described in Supplementary Methods . Synonymous and intronic variants were excluded as well as variants present in population frequency databases (in 1000Genomes, ExAC, ESP or GoNL).
For comparison, the somatic mutation data from 915 colorectal adenocarcinoma exomes (Muzny et al, 2012 (link); Seshagiri et al, 2012 (link); Giannakis et al, 2016 (link)) was retrieved from The cancer genome atlas (TCGA) using cBioPortal (Cerami et al, 2012 ; Gao et al, 2013 (link)).
For comparison, the somatic mutation data from 915 colorectal adenocarcinoma exomes (Muzny et al, 2012 (link); Seshagiri et al, 2012 (link); Giannakis et al, 2016 (link)) was retrieved from The cancer genome atlas (TCGA) using cBioPortal (Cerami et al, 2012 ; Gao et al, 2013 (link)).
