Circulating tumour-derived KRAS mutations in pancreatic cancer cases are predominantly carried by very short fragments of cell-free DNA
Abstract
BACKGROUND: The DNA released into the bloodstream by malignant tumours· called circulating tumour DNA (ctDNA), is often a small fraction of total cell-free DNA shed predominantly by hematopoietic cells and is therefore challenging to detect. Understanding the biological properties of ctDNA is key to the investigation of its clinical relevance as a non-invasive marker for cancer detection and monitoring. METHODS: We selected 40 plasma DNA samples of pancreatic cancer cases previously reported to carry a KRAS mutation at the 'hotspot' codon 12 and re-screened the cell-free DNA using a 4-size amplicons strategy (57 bp, 79 bp, 167 bp and 218 bp) combined with ultra-deep sequencing in order to investigate whether amplicon lengths could impact on the capacity of detection of ctDNA, which in turn could provide inference of ctDNA and non-malignant cell-free DNA size distribution. FINDINGS: Higher KRAS amplicon size (167 bp and 218 bp) was associated with lower detectable cell-free DNA mutant allelic fractions (p < 0·0001), with up to 4·6-fold (95% CI: 2·6-8·1) difference on average when comparing the 218bp- and the 57bp-amplicons. The proportion of cases with detectable KRAS mutations was also hampered with increased amplicon lengths, with only half of the cases having detectable ctDNA using the 218 bp assay relative to those detected with amplicons less than 80 bp. INTERPRETATION: Tumour-derived mutations are carried by shorter cell-free DNA fragments than fragments of wild-type allele. Targeting short amplicons increases the sensitivity of cell-free DNA assays for pancreatic cancer and should be taken into account for optimized assay design and for evaluating their clinical performance. FUNDING: IARC; MH CZ - DRO; MH SK; exchange program between IARC and Sao Paulo medical Sciences; French Cancer League.
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BibTeX
@article{zvereva2026circulating,
title = {{Circulating tumour-derived KRAS mutations in pancreatic cancer cases are predominantly carried by very short fragments of cell-free DNA}},
author = {Maria Zvereva and Gabriel Roberti and Geoffroy Durand and Catherine Voegele and Minh Dao Nguyen and Tiffany M. Delhomme and Priscilia Chopard and Eleonora Fabianova and Zora Adamcakova and Ivana Holcatova and Lenka Foretova and Vladimir Janout and Paul Brennan and Matthieu Foll and Graham B. Byrnes and James D. Mckay and Ghislaine Scelo and Florence Le Calvez-Kelm},
journal = {EBioMedicine},
year = {2026},
month = oct,
doi = {10.1016/j.ebiom.2019.09.042},
url = {https://hal.science/hal-05842048v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Circulating tumour-derived KRAS mutations in pancreatic cancer cases are predominantly carried by very short fragments of cell-free DNA
AU - Maria Zvereva
AU - Gabriel Roberti
AU - Geoffroy Durand
AU - Catherine Voegele
AU - Minh Dao Nguyen
AU - Tiffany M. Delhomme
AU - Priscilia Chopard
AU - Eleonora Fabianova
AU - Zora Adamcakova
AU - Ivana Holcatova
AU - Lenka Foretova
AU - Vladimir Janout
AU - Paul Brennan
AU - Matthieu Foll
AU - Graham B. Byrnes
AU - James D. Mckay
AU - Ghislaine Scelo
AU - Florence Le Calvez-Kelm
PY - 2026
DA - 2026/10/28
JO - EBioMedicine
DO - 10.1016/j.ebiom.2019.09.042
UR - https://hal.science/hal-05842048v1
AB - BACKGROUND: The DNA released into the bloodstream by malignant tumours· called circulating tumour DNA (ctDNA), is often a small fraction of total cell-free DNA shed predominantly by hematopoietic cells and is therefore challenging to detect. Understanding the biological properties of ctDNA is key to the investigation of its clinical relevance as a non-invasive marker for cancer detection and monitoring. METHODS: We selected 40 plasma DNA samples of pancreatic cancer cases previously reported to carry a KRAS mutation at the 'hotspot' codon 12 and re-screened the cell-free DNA using a 4-size amplicons strategy (57 bp, 79 bp, 167 bp and 218 bp) combined with ultra-deep sequencing in order to investigate whether amplicon lengths could impact on the capacity of detection of ctDNA, which in turn could provide inference of ctDNA and non-malignant cell-free DNA size distribution. FINDINGS: Higher KRAS amplicon size (167 bp and 218 bp) was associated with lower detectable cell-free DNA mutant allelic fractions (p < 0·0001), with up to 4·6-fold (95% CI: 2·6-8·1) difference on average when comparing the 218bp- and the 57bp-amplicons. The proportion of cases with detectable KRAS mutations was also hampered with increased amplicon lengths, with only half of the cases having detectable ctDNA using the 218 bp assay relative to those detected with amplicons less than 80 bp. INTERPRETATION: Tumour-derived mutations are carried by shorter cell-free DNA fragments than fragments of wild-type allele. Targeting short amplicons increases the sensitivity of cell-free DNA assays for pancreatic cancer and should be taken into account for optimized assay design and for evaluating their clinical performance. FUNDING: IARC; MH CZ - DRO; MH SK; exchange program between IARC and Sao Paulo medical Sciences; French Cancer League.
SN - 2352-3964
ER -