Circulating Tumor Cells and Cell-Free DNA in Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is detected late in the disease process and has an extremely poor prognosis. A blood-based biomarker that can enable early detection of disease, monitor response to treatment, and potentially allow for personalized treatment would be of great benefit. This review analyzes the literature regarding two potential biomarkers, circulating tumor cells (CTCs) and cell-free DNA (cfDNA), with regard to pancreatic ductal adenocarcinoma. The origin of CTCs and the methods of detection are discussed and a decade of research examining CTCs in pancreatic cancer is summarized, including both levels of CTCs and analyzing their molecular characteristics and how they may affect survival in both advanced and early disease and allow for treatment monitoring. The origin of cfDNA is discussed, and the literature over the past 15 years is summarized. This includes analyzing cfDNA for genetic mutations and methylation abnormalities, which have the potential to be used for the detection and prognosis of pancreatic ductal adenocarcinoma. However, the research certainly remains in the experimental stage, warranting future large trials in these areas.