BACKGROUNDRecently,mutations in the epidermal growth factor receptor(EGFR) gene were reported to correlate with EGFR tyrosine kinase inhibitor(TKI) response.In this study,relationship between mutations of EGFR in plasma and pleural effusion and responses to gefitinib was investigated in pretreated patients with advanced non-small cell lung cancer(NSCLC).

METHODSThe circulating free DNA was isolated from the plasma of 53 cases and pleural effusion of another 10 cases and analysed for EGFR mutations by LightCycle PCR method.Relationship between EGFR mutations and response to gefitinib was analysed with Chi-square test.

RESULTSEGFR mutations were found in 17 of 63 cases(27.0%).EGFR mutations were frequently present in females(P=0.024) and non-smokers(P=0.021).Patients with EGFR mutations had a significantly better response rate compared to that of the wild-type patients(P=0.000).

CONCLUSIONSThe EGFR mutations exist in the plasma and the pleural effusion from patients with advanced NSCLC.These mutations can be detected with LightCycle PCR method which is highly specific and sensitive and easy to perform compared with the direct sequencing.It will enable us to get a potential implication in the diagnosis and targeted therapy of NSCLC at late stage.