Whole Genome Sequencing Informs Therapeutic Selection for Pancreatic Cancer

Pancreatic cancer remains one of the most lethal of malignancies and a major health burden. We performed whole genome sequencing and CNV analysis of 100 pancreatic ductal adenocarcinomas. Chromosomal rearrangements leading to gene disruption were frequent, affecting genes known to be important in pancreatic cancer (TP53, SMAD4, CDKN2A, ARID1A, ROBO2) and novel candidate drivers of pancreatic carcinogenesis (KDM6A and PREX2). Patterns of structural variation classified PDAC into 4 subtypes with potential clinical utility: stable, locally rearranged, scattered and unstable. A significant proportion harboured focal amplifications, many of which contained druggable oncogenes (ERBB2, MET, FGFR1, CDK6, PIK3R3, and PIK3CA), but at low individual frequency. Genomic instability co-segregated with inactivation of DNA maintenance genes (BRCA1, BRCA2, PALB2 or RPA1), and a mutational signature of DNA damage repair deficiency. This subgroup was associated with response to platinum-based therapy and defines candidate biomarkers of therapeutic responsiveness.