A non-invasive system for monitoring resistance to EGFR tyrosine kinase inhibitors with plasma DNA

2^nd World Congress on Biomarkers & Clinical Research

12-14 September 2011 Baltimore, USA

Naoko Sueoka-Aragane, Tomomi Nakamura, Kentaro Iwanaga, Akemi Sato, Kazutoshi Komiya, Tomonori Abe, Norio Ureshino, Shinichiro Hayashi, Toshiya Hosomi, Mitsuharu Hirai, Eisaburo Sueoka and Shinya Kimura

Scientific Tracks Abstracts: J Mol Biomark Diagn

Abstract :

EGFR tyrosine kinase inhibitors (EGFR-TKIs) have great response to lung adenocarinoma with EGFR activating mutations. However, acquired resistance eventually developed, and the half of these patients has the gatekeeper T790M mutation of EGFR in lung cancer tissue. A non-invasive mutation detection system is desired considering the diffi culty in obtaining tissue specimens during disease progression?the majority of lung cancer recurrences occur in distant sites. We report a novel non-invasive monitoring system, MBP-QP (mutation-biased PCR and quenching probe) method, to detect the mutation using plasma DNA. Th e MBP-QP method combines mutated-biased PCR and genotyping based on analysis of the melting curve of the probe DNA binding the target mutated site using a fl uorescence quenching probe system. Th e detection limit was two copies of control plasmid, and 0.2 ng of genomic DNA isolated from a lung caner cell line harboring T790M. 0.3 % mutant plasmid could be detected in the mixture of plasmids inserted with EGFR exon 20 with or without T790M. With this method, T790M mutations were detected in plasma DNA of 50% of patients who acquired resistance, but not in primary EGFR-TKI non-responders, patients responding to treatment, or patients not treated with EGFR-TKI, which is consistent with the clinical course. Th e non-invasive MBP-QP method enabled us to monitor T790M repeatedly and will be useful for determining appropriate lung cancer treatment strategies in practice.