Total and mutated EGFR quantification in cell-free DNA from non-small cell lung cancer patients detects tumor heterogeneity and presents prognostic value
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Mutation analysis of epidermal growth factor receptor (EGFR) gene is essential for treatment selection in non-small cell lung cancer (NSCLC). Analysis is usually performed in tumor samples. We evaluated the clinical utility of EGFR analysis in plasma cell-free DNA (cfDNA) from patients under treatment with EGFR inhibitors. We selected 36 patients with NSCLC and EGFR-activating mutations. Blood samples were collected at baseline and during treatment with EGFR inhibitors. Wild-type EGFR, L858R, delE746-A750, and T790M mutations were quantified in cfDNA by droplet digital PCR. Stage IV patients had higher total circulating EGFR copy levels than stage I (3523 vs. 1003 copies/mL; p < 0.01). There was high agreement for activating mutations between baseline cfDNA and tumor samples, especially for L858R mutation (kappa index = 0.679; p = 0.001). In 34 % of advanced NSCLC patients, we detected mutations in cfDNA not previously detected in tumor samples and double mutations in 17 %. Patients with baseline total EGFR copy levels above the median presented decreased overall survival (OS) (341 vs. 870 days, p < 0.05) and progression-free survival (PFS) (238 vs. 783 days; p < 0.05) compared with those with total EGFR copy levels below the median. Patients with baseline concentrations of activating mutations above the median (94 copies/mL) had lower OS (317 vs. 805 days; p < 0.05) and PFS (195 vs. 724 days; p < 0.05). During follow-up, T790M resistance mutation was detected in 53 % of patients. Total and mutated EGFR analysis in cfDNA seems a relevant tool to characterize the molecular profile and prognosis of NSCLC patients harboring EGFR mutations.
KeywordsCell-free DNA Droplet digital PCR Non-small cell lung cancer EGFR mutation Prognosis Tumor heterogeneity
Epidermal growth factor receptor
Non-small cell lung cancer
Droplet digital PCR
Tyrosine kinase inhibitors
Peripheral blood mononuclear cells
We would like to thank Dra. María Romero for her support in manuscript preparation and the Biobank of the University of Navarra for its collaboration.
- 11.Lozano MD, Zulueta JJ, Echeveste JI, Gurpide A, Seijo LM, Martin-Algarra S, et al. Assessment of epidermal growth factor receptor and K-ras mutation status in cytological stained smears of non-small cell lung cancer patients: correlation with clinical outcomes. Oncologist. 2011;16(6):877–85.CrossRefPubMedPubMedCentralGoogle Scholar
- 19.Altman DG. Practical statistics for medical research. 1st ed. London; New York: Chapman and Hall; 1991.Google Scholar
- 23.Mok T, YL W, Lee JS, CJ Y, Sriuranpong V, Sandoval-Tan J, et al. Detection and dynamic changes of EGFR mutations from circulating tumor DNA as a predictor of survival outcomes in NSCLC patients treated with first-line intercalated erlotinib and chemotherapy. Clin Cancer Res. 2015;21(14):3196–203.CrossRefPubMedGoogle Scholar
- 32.Paweletz CP, Sacher A, Raymond CK, Alden RS, O’Connell A, Mach SL, et al. Bias-corrected targeted next-generation sequencing for rapid, multiplexed detection of actionable alterations in cell-free DNA from advanced lung cancer patients. Clin Cancer Res. 2016;22(4):915–22.CrossRefPubMedGoogle Scholar
- 38.Seki Y, Fujiwara Y, Kohno T, Takai E, Sunami K, Goto Y, et al. Picoliter-droplet digital polymerase chain reaction-based analysis of cell-free plasma DNA to assess EGFR mutations in lung adenocarcinoma that confer resistance to tyrosine-kinase inhibitors. Oncologist. 2016;21(2):156–64.CrossRefPubMedGoogle Scholar