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Detection of EGFR mutations in plasma DNA from lung cancer patients by mass spectrometry genotyping is predictive of tumor EGFR status and response to EGFR inhibitors.

ABSTRACT: AIMS:EGFR mutations now guide the clinical use of EGFR-targeted therapy in lung cancer. However, standard EGFR mutation analysis requires a minimum amount of tumor tissue, which may not be available in certain situations. In this study, we combined a mass spectrometry genotyping assay (Sequenom) with a mutant-enriched PCR (ME-PCR) to detect EGFR mutations in free plasma DNA from patients with lung cancer. METHOD:DNAs were extracted from 31 plasma samples from 31 patients and analyzed by both methods for EGFR Exon 19 deletion and EGFR L858R mutation. Results in plasma DNA samples were compared with EGFR mutation status obtained in tumor DNA (18/31 EGFR mutant). The relationship of EGFR mutation status in tumor and/or plasma samples to overall survival was assessed. RESULTS:The EGFR mutation status in plasma DNA was identical to the primary tumor in 61% of patients (19/31). By mass spectrometry genotyping, the plasma samples contained mutant DNA corresponding to 5/14 EGFR Exon 19 deletions and 3/4 EGFR L858R mutations previously diagnosed in the matched tumors. Two samples were positive in plasma DNA but negative in primary tumor tissue. Results were similar for samples studied by ME-PCR. For patients treated with erlotinib, overall survival was correlated with the presence of EGFR mutation in plasma and/or tumor tissue (p=0.002), with the two patients positive only in plasma DNA showing responses and favorable outcomes. CONCLUSION:The detection of EGFR mutations in plasma DNA samples by mass spectrometry genotyping and ME-PCR is feasible. A positive EGFR result in plasma DNA has a high predictive value for tumor EGFR status and for favorable clinical course on EGFR-targeted therapy and could therefore be useful in guiding clinical decisions in patients with insufficient or unavailable tumor specimens.

SUBMITTER: Brevet M

PROVIDER: S-EPMC3282180 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Detection of EGFR mutations in plasma DNA from lung cancer patients by mass spectrometry genotyping is predictive of tumor EGFR status and response to EGFR inhibitors.

Brevet Marie M Johnson Melissa L ML Azzoli Christopher G CG Ladanyi Marc M

Lung cancer (Amsterdam, Netherlands) 20101203 1

<h4>Aims</h4>EGFR mutations now guide the clinical use of EGFR-targeted therapy in lung cancer. However, standard EGFR mutation analysis requires a minimum amount of tumor tissue, which may not be available in certain situations. In this study, we combined a mass spectrometry genotyping assay (Sequenom) with a mutant-enriched PCR (ME-PCR) to detect EGFR mutations in free plasma DNA from patients with lung cancer.<h4>Method</h4>DNAs were extracted from 31 plasma samples from 31 patients and analy ...[more]

PMID: 21130517

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Project description:Analysis and detection of micronutrients is important for the reduction of the global burden of malnutrition-related disease. A relatively new technique, plasma pencil atmospheric mass spectrometry (PPAMS) was applied in a comprehensive evaluation for rapid, simultaneous detection of the key micronutrients zinc, iron, folate, vitamin A, and iodine. PPAMS was performed through the coupling of a low-temperature plasma pencil to an atmospheric mass spectrometer. The effectiveness of the PPAMS system was demonstrated through the generation of characteristic mass spectra and tandem mass spectra on neat micronutrient powders suspended on double-sided tape. The analytical performance and ability to qualitatively separate out the nutrients from a complex biological solution and each other was then assessed through the application of PPAMS on a sample matrix of micronutrients in porcine plasma in which nutrient concentration is varied from high blood level concentrations (HBLCs) to low blood level concentrations (LBLCs). A multivariate analysis method, principal component analysis (PCA), was then used to qualitatively separate the fragments obtained by nutrient type. The resulting plots of PCA scores of the positive-ion spectra from each mixed sample showed excellent separation of HBLCs and LBLCs of single nutrients at the 95% confidence level (Wagner et al. Langmuir 2001, 17, 4649-4660). The associated plots of PCA loadings showed that key loadings could be attributed to the expected micronutrient fragments. The PPAMS technique was successfully demonstrated and compared with traditional MS techniques: time-of-flight secondary ion mass spectrometry (ToF-SIMS) and electrospray ionization mass spectrometry (ESI-MS). Separation of the nutrients at concentrations relevant for human blood-based nutrient detection was possible by both ESI-MS and PPAMS. However, only PPAMS could detect the nutrients at physiological concentrations from porcine plasma. ToF-SIMS could detect the nutrients from plasma solution but required 5 to 1000-times higher concentrations of folate, vitamin A, and iodine to achieve adequate separation of the micronutrients by PCA.

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Dataset Information

Detection of EGFR mutations in plasma DNA from lung cancer patients by mass spectrometry genotyping is predictive of tumor EGFR status and response to EGFR inhibitors.

Publications

Detection of EGFR mutations in plasma DNA from lung cancer patients by mass spectrometry genotyping is predictive of tumor EGFR status and response to EGFR inhibitors.

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