WEDNESDAY, Aug. 16, 2017 (HealthDay News) -- A single-color digital polymerase chain reaction (PCR) assay can detect cancer mutations directly from circulating DNA from patients, according to research published online Aug. 14 in the Journal of Molecular Diagnostics.
Christina Wood-Bouwens, from Stanford University in Palo Alto, Calif., and colleagues describe a single-color digital PCR assay that detects and quantifies cancer mutations directly from circulating DNA from the plasma of patients with cancer. The approach determines an absolute count of the mutation- and wild-type-bearing DNA molecules present in the sample, relying on a double-stranded DNA intercalator dye and paired allele-specific DNA primer sets.
The researchers note that the cell-free DNA assay used an input of 1 ng of nonamplified DNA, which was approximately 300 genome equivalents. The molecular limit of detection was about three mutation DNA genome-equivalent molecules per assay reaction. Sensitivity was 0.10 percent for detecting the BRAF V600E and KRAS G12D mutations, using more genome equivalents as input. Several mutation assays were developed that were specific to the cancer driver mutations of patients' tumors, and these mutations were detected directly from the nonamplified, circulating cell-free DNA.
"This rapid and high-performance digital PCR assay can be configured to detect specific cancer mutations unique to an individual cancer, making it a potentially valuable method for patient-specific longitudinal monitoring," the authors write.