For cases E4051 and E6526 we sequenced both tumor (peripheral blood leucocyte) and constitutional (cultured T-cell) DNA. T-cells were isolated from anticoagulated peripheral blood using CD3 MicroBeads and cultured using a T-cell Activation/Expansion kit (Miltenyi Biotec, Bisley, UK). Samples were prepared for exome sequencing using the Agilent SureSelect kit (Agilent Technologies, Palo Alto, CA, USA) (Human All Exon 50 Mb) and then sequenced on an Illumina HiSeq 2000 (Illumina, Great Abington, UK) at the Wellcome Trust Centre for Human Genetics, Oxford, UK. Exome sequencing of ULSAM1182, ULSAM1242 and ULSAM1356 (peripheral blood leukocyte DNA only) was performed by SciLifeLab (Stockholm, Sweden). Sequence data from all five samples were analyzed using a custom bioinformatic pipeline as previously described.18 (link)