{"entity":{"id":"paper-cohen-ctdna-protein-liquid-biopsy-pancreatic-pnas-2017","kind":"paper","name":"Combined circulating tumor DNA and protein biomarker-based liquid biopsy for the earlier detection of pancreatic cancers","aka":[],"tldr":"A blood test combining KRAS mutations with four proteins found 64% of 221 operable pancreatic cancers while wrongly flagging only one of 182 people without cancer.","summary":"Blood tests for KRAS gene mutations were combined with carefully thresholded protein biomarkers in 221 patients with resectable pancreatic ductal adenocarcinoma and 182 control patients without known cancer. KRAS mutations were detected in the plasma of 66 patients (30%), and every mutation found in plasma was identical to that subsequently found in the primary tumour (100% concordance). KRAS with four thresholded protein biomarkers increased sensitivity to 64%. Only one of the 182 control plasma samples was positive for any DNA or protein biomarker (99.5% specificity).","asOf":"2026-09-24","links":[{"label":"Cohen et al., PNAS 2017: KRAS ctDNA plus protein markers in 221 resectable cancers","url":"https://doi.org/10.1073/pnas.1704961114"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/28874546/"}],"tags":[],"related":[],"cancers":["pancreatic","resectable-pdac"],"sections":[],"technologies":["liquid-biopsy","mced","proteomics"],"targets":["kras"],"drugs":[],"companies":[],"institutions":["johns-hopkins"],"pathways":[],"terms":["ctdna","cfdna","ca19-9"],"trials":[],"people":["bert-vogelstein","nickolas-papadopoulos"],"bottlenecks":[],"keyPapers":[],"journals":["pnas"],"dependsOn":[],"notes":[],"journal":"PNAS","year":2017,"doi":"10.1073/pnas.1704961114","pmid":"28874546","authors":"Cohen JD, Javed AA, Thoburn C, et al.","paperType":"observational","findings":["Plasma KRAS in only 30% of resectable cancers, with 100% concordance with the tumour.","Adding four proteins raised sensitivity to 64% at 99.5% specificity."],"whatItMeans":"It quantifies how little DNA an operable pancreatic cancer sheds and why every serious early detection panel pairs DNA with proteins.","caveats":["Case-control design overstates performance against a screening population.","Resectable cancers are already symptomatic in most cases."],"changedPractice":false,"participants":403},"route":"/key-papers/paper-cohen-ctdna-protein-liquid-biopsy-pancreatic-pnas-2017/","neighbours":{"cancer":[{"id":"pancreatic","kind":"cancer","name":"Pancreatic ductal adenocarcinoma","route":"/cancers/pancreatic/"},{"id":"resectable-pdac","kind":"cancer","name":"Resectable pancreatic ductal adenocarcinoma","route":"/cancers/resectable-pdac/"}],"technology":[{"id":"liquid-biopsy","kind":"technology","name":"Liquid biopsy (ctDNA)","route":"/technologies/liquid-biopsy/"},{"id":"mced","kind":"technology","name":"Multi-cancer early detection (MCED)","route":"/technologies/mced/"},{"id":"proteomics","kind":"technology","name":"Proteomics & phosphoproteomics","route":"/technologies/proteomics/"}],"target":[{"id":"kras","kind":"target","name":"KRAS","route":"/targets/kras/"}],"institution":[{"id":"johns-hopkins","kind":"institution","name":"Johns Hopkins Hospital / Sidney Kimmel Comprehensive Cancer Center","route":"/institutions/johns-hopkins/"}],"term":[{"id":"ca19-9","kind":"term","name":"CA 19-9","route":"/terms/ca19-9/"},{"id":"cfdna","kind":"term","name":"Cell-free DNA (cfDNA)","route":"/terms/cfdna/"},{"id":"ctdna","kind":"term","name":"Circulating tumour DNA (ctDNA)","route":"/terms/ctdna/"}],"person":[{"id":"bert-vogelstein","kind":"person","name":"Bert Vogelstein","route":"/people/bert-vogelstein/"},{"id":"nickolas-papadopoulos","kind":"person","name":"Nickolas Papadopoulos","route":"/people/nickolas-papadopoulos/"}],"journal":[{"id":"pnas","kind":"journal","name":"Proceedings of the National Academy of Sciences","route":"/journals/pnas/"}]}}