Brovkina O I, Gordiev M G, Gusev O A, Nikitin A G and Khodyrev D S
Federal Medical and Biological Agency, Russia
Posters & Accepted Abstracts: J Stem Cell Res Ther
The presence of activating mutations in the EGFR gene is a prognostic marker of susceptibility to target therapy by Tyrosine Kinase Inhibitors (TKI). Now it is possible to determine in the plasma activating mutation in 19-21 exon as well as T790M mutations in exon 20, which is marker refractory to TKI. The aim of this study was to compare mutation status in FFPE tissue and plasma samples and the evaluate diagnostic characteristics of real-time wild-type blocking PCR (LNA-clamp) assay, digital PCR approach (dPCR) and routine approaches, which are used for tissue analysis â?? Sanger sequencing and realâ??time PCR. The study included 89 patients with advanced NSCLC with known mutation status in FFPE tissue. L858R, del19 and T790M mutations were determined in corresponding blood plasma samples. Sanger sequencing and realâ??time PCR revealed sensitivity in plasma samples less than 20%. Comparison of the EGFR mutations status in plasma by LNA-clamp real-time PCR and dPCR and tumor revealed concordance 88.7% [95% CI: 85â??92%], sensitivity â?? 83.3% [95% CI: 76â??90%], specificity-100%. Comparison of these two PCR approaches revealed 100% concordance of results in plasma samples, despite the higher analytical capabilities of dPCR, that was received with artificial plasmid positive controls application. It had shown a potential of reliable detection of cDNA with mutation amount less than 1% (5- 10 copies mutant gene per reaction) with excess background of wild type DNA (ratio DNA mutation to wild-type DNA 1: 10000).
Brovkina O I has completed her PhD from State Research Center GosNIIgenetika. At present, she is a Postdoctoral fellow in the Genetic Laboratory of Government Scientific Clinical Center of Federal Medical and Biological Agency of Russia. She has published 4 papers in reputed journals in Russian language.
Email: brov.olia@gmail.com