New Epigenetic Drivers of Cancers

Mutations in proteins that control chromatin dynamics contribute to tumorigenesis. Exome sequencing—the targeted sequencing of all protein-coding regions in the human genome—now offers an unprecedented opportunity for systematic, genome-wide discovery of somatic mutations in tumor tissue. On page 1199 of this issue, Jiao et al. (1) have applied this pioneering technique to identify common genetic mutations underlying pancreatic neuroendocrine tumors (PanNETs), a class of tumors that frequently arise from pancreatic islet cells. This report adds to a growing number of studies that use exome sequencing to explore cancers with unknown or poorly understood genetic etiology (2–8).