DNA was isolated from tumor specimens, and normal DNA was isolated from leukocytes in peripheral blood. Whole exome sequencing was performed on DNA from all 27 blood and tumor samples. We extracted the DNA from the paired tumor and peripheral blood leukocytes using QIAamp DNA Mini Kit according to the manufacturer’s protocol (Qiagen, Valencia, CA). Genomic DNA samples were constructed into Illumina paired-end precapture libraries and prepared using protocols recommended by Illumina. Captured DNA libraries were sequenced with the Illumina HiSeq 2000 Genome Analyzer to an average coverage of 144X, yielding 150 (2 × 75) base pairs from the final library fragments. Reads were aligned to the hg19 (GRCh37) build using the Burrows-Wheeler Aligner (BWA)(16 (link)), and then Genome Analysis Toolkit (GATK) (17 (link)) was used for base quality score recalibration, indel realignment, and duplicate read removal. The MuTect algorithm (18 ) was used to identify somatic single nucleotide variants (SNVs) in whole-exome sequencing data. MuTect identifies candidate somatic SNVs by Bayesian statistical analysis of bases and their qualities in the tumor and normal BAM files at a given genomic locus.