Esophageal cancer intratumor heterogeneity revealed by multi-region whole exome sequencing and aCGH

Cancer is a disease of the genome. Many genomic abnormalities have been found in a variety of cancer types, which are believed to be attributable to tumorigenesis as well as resistance to treatment and recurrence. Genomic heterogeneity in the same type of cancer or within a tumor reveals the complexity of cancer biology so that intratumor heterogeneity has become an inherent feature of cancer. In this study, we use whole-exome sequencing and array comparative genomic hybridization technology to examine the mutational profiling and copy number changes from multi-region samples within an esophageal cancer in order to understand the genomic phylogeny in the evolution of intratumor heterogeneity in esophageal cancer. Four spatially separated tumor samples and a fifth adjacent non-tumor sample were harvested from two patients with esophageal squamous cell carcinomas. An additional, local metastatic sample was obtained from one of the patients. DNAs from these samples were subjected to whole-exome sequencing and array comparative genomic hybridization. Comprehensive bioinformatic analyses were performed.