TY - JOUR T1 - Real-time molecular imaging of EGFR mutations using fibred confocal fluorescence microscopy (FCFM) JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - P3118 AU - Maxime Patout AU - Mathieu Salaun AU - Pierre Bohn AU - Xavier Brune AU - Anthony Romieu AU - Nasrin Vasseur AU - Richard Sesboüé AU - Pierre-Yves Renard AU - Luc Thiberville Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/P3118.abstract N2 - Introduction: EGFR mutations are routinely explored in lung adenocarcinoma (ADC) by sequencing tumoral DNA. The objective of the study was to assess the diagnostic accuracy of a specific fluorescent tracer for in situ and real time EGFR-mutations molecular imaging.Methods: Four human ADC cell lines were used as xenographs in 3 nude mice groups. Group A received HCC827 and H1650 cell lines that harbour DelE746-A750 (TKI-sensitive) EGFR mutation. Group B received the A549 cell line that contains wild-type EGFR. Group C received the H1975 cell line that harbours both the T790M (TKI-resistance) and the L858R (TKI sensitive) EGFR mutations. The fluorescent tracer was synthesized in our laboratory by the addition of a fluorescein to the erlotinib molecule. Fresh tumors were excised and exposed to a 1 µM tracer solution in PBS for one hour. After multiple washings, real-time molecular imaging was performed using FCFM. The median fluorescence intensity (MFI) was recorded for each tumor.Results: 19 lesions were imaged (Group A =11, Group B =4; Group C =4). The MFI was significantly higher in the 2 groups harbouring mutated-EGFR (groups A and C) compared to wild-type EGFR tumors (group B) (A: 757.3 arbitrary units (A.U) and C: 823.8 A.U vs. B: 307.5 A.U ; p<0.05, Kruskal-Wallis test). Using a cut-off MFI value of 386 A.U, the tracer showed a Se=100% and Sp=100% for mutated EGFR tumor.Conclusion: Our fluorescent tracer was able to distinguish tumors with EGFR-mutations, both with sensitive or resistant phenotype, from EGFR-wild-type in real time using FCFM. If confirmed by using fresh human tumors, the technique may be used as a rapid-on-site test to select tumors requiring sequencing. ER -