Evaluation of clinical outcomes of pancreatic cancer patients using circulating nucleic acids
The incidence of pancreatic ductal adenocarcinomas (PDAC) is increasing, and, owing to its malignant features and poor prognosis, it is becoming the second or third leading cause of cancer death in many countries. Somatic mutations in KRAS, CDKN2A, TP53, and SMAD4 are frequently observed in PDAC (1). Bernard et al. examined circulating nucleic acid levels in liquid biopsies from 194 pancreatic cancer patients from April 2015 to October 2017 (2). Droplet quantitative digital polymerase chain reaction (ddPCR) was used to determine KRAS mutant allele fractions (MAFs) from circulating tumor cell DNA (ctDNA) and exosomal DNA (exoDNA) purified from a large series of prospectively collected plasma from patients. The authors showed that the baseline levels of CA19-9, a PDAC marker, and exoDNA and ctDNA affect the prognosis and overall survival of PDAC patients. In a longitude analysis, a MAF peak above 1% in exoDNA was significantly associated with radiological progression. This study indicated that longitude monitoring of exoDNA and ctDNA using liquid biopsies provides predictive and prognostic information for therapeutic intervention of pancreatic cancers with poor prognosis and metastasis.