KRASmutations in blood circulating cell-free DNA: a pancreatic cancer case-control

Abstract

The utility of KRAS mutations in plasma circulating cell-free DNA (cfDNA) samples as non-invasive biomarkers for the detection of pancreatic cancer has never been evaluated in a large case-control series. We applied a KRAS amplicon-based deep sequencing strategy combined with analytical pipeline specifically designed for the detection of low-abundance mutations to screen plasma samples of 437 pancreatic cancer cases, 141 chronic pancreatitis subjects, and 394 healthy controls. We detected mutations in 21.1% (N=92) of cases, of whom 82 (89.1%) carried at least one mutation at hotspot codons 12, 13 or 61, with mutant allelic fractions from 0.08% to 79%. Advanced stages were associated with an increased proportion of detection, with KRAS cfDNA mutations detected in 10.3%, 17,5% and 33.3% of cases with local, regional and systemic stages, respectively. We also detected KRAS cfDNA mutations in 3.7% (N=14) of healthy controls and in 4.3% (N=6) of subjects with chronic pancreatitis, but at significantly lower allelic fractions than in cases. Combining cfDNA KRAS mutations and CA19-9 plasma levels on a limited set of case-control samples did not improve the overall performance of the biomarkers as compared to CA19-9 alone. Whether the limited sensitivity and specificity observed in our series of KRAS mutations in plasma cfDNA as biomarkers for pancreatic cancer detection are attributable to methodological limitations or to the biology of cfDNA should be further assessed in large case-control series.

Enrichment of short mutant cell-free DNA fragments enhanced detection of pancreatic cancer

“…We compared the performance of our approach in measuring KRAS mutations with that in previous reports using PCR- or NGS-based methods ( Table S4 ). (Allenson et al, 2017; Berger et al, 2016; Brychta et al, 2016; Cheng et al, 2017; Cohen et al, 2017; Hadano et al, 2016; Kim et al, 2018; Kinugasa et al, 2015; Le Calvez-Kelm et al, 2016; Pietrasz et al, 2017; Sausen et al, 2015; Sefrioui et al, 2017; Takai et al, 2015) Across 13 high-quality studies, the detection rate of the KRAS mutations in plasma ranged from to 21% to 76% ( Fig. 2A ).…”

The diagnostic accuracy of circulating free DNA for the detection of KRAS mutation status in colorectal cancer: A meta‐analysis

“…As obvious limitations exist while detecting gene mutations in tumor tissues, cfDNA has attracted more and more attention due to its more feasible, timely, and less invasive nature . For example, in pancreatic cancer, KRAS mutations in cfDNA were evaluated using deep sequencing assay as non‐invasive biomarkers in a large case‐control study and its changes between preoperation and postoperation were suggested to be a predictive biomarker for survival and treatment response . Currently, the KRAS status of primary tumors in CRC patients is considered as a reliable selection criterion prior to the application of EGFR‐targeted therapy .…”

Early detection and therapeutics

“…In another study, analysing the role of ctDNA in the early detection of small-cell lung cancer, the TP53 mutations were present in the plasma of 11% of the 225 non-cancer controls (Fernandez-Cuesta et al, 2016). Lastly, the KRAS cell-free DNA mutations could be detected in 3.7% of healthy controls and in 4.3% of patients with chronic pancreatitis in a study focused on pancreatic cancer detection (Calvez-Kelm et al, 2016).…”