Bernard V, et al. - In 37 disease control individuals and 194 patients undergoing treatment for localized or metastatic pancreatic adenocarcinoma from April 7, 2015, through October 13, 2017, researchers studied the clinical utility of circulating tumor cell DNA (ctDNA) and exosome DNA (exoDNA). The concordance rate of KRAS mutations in surgically resected tissue detected in liquid biopsy samples was more than 95%. Longitudinal monitoring of exoDNA provides unique predictive information on the outcome of neoadjuvant therapy in localized disease and in anticipating progression in the metastatic setting although the baseline CA19-9, exoDNA, and ctDNA cargo have a prognostic effect. Serial liquid biopsies might provide an attractive alternative strategy to map tumor evolution in real time in contrast to the challenges of repetitive tissue biopsies for visceral cancers, providing an unprecedented insight into how the pancreatic ductal adenocarcinoma (PDAC) genome adapts to and eventually becomes recalcitrant to therapy.