Circulating tumor DNA (ctDNA) measurements can be used to estimate tumor burden, but avoiding false-positives is a challenge. We evaluated digital next-generation sequencing (NGS) as a ctDNA detection method. Plasma KRAS and GNAS hotspot mutation levels were measured in 140 subjects including 67 with pancreatic ductal adenocarcinoma, and 73 healthy and disease controls.
To limit chemical modifications of DNA that yield false-positive mutation calls, plasma DNA was enzymatically pre-treated, after which DNA was aliquoted for digital detection of mutations (up to 384 aliquots/sample) by PCR and NGS. A digital NGS score of two standard deviations above the mean in controls was considered positive. Read more . . .