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 . . .
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.