Detection of epidermal growth factor receptor mutation in transbronchial aspiration cytology of non-small cell lung cancer

Abstract

7175 Background: Somatic mutations of epidermal growth factor receptor (EGFR) strongly associate with objective response to EGFR tyrosine kinase inhibitors. There are some problems to practically use it as prognostic markers. Since it is difficult to obtain sufficient tumor samples from non-small cell lung cancer (NSCLC) patients, they are often diagnosed by cytological procedure alone. Therefore, it is very useful if EGFR mutations are able to be detected in cytological samples. The aims of this study are to detect EGFR mutations in the samples of transbronchial aspiration cytology (TBAC) by using direct sequencing and Scorpion ARMS method, and to compare the sensitivities of these methods. Patients and Methods: 94 patients diagnosed as NSCLC in our institute were enrolled in this study, consisting of 63 males and 31 females with a median age of 66. In cytologic diagnosis, they were adenocarcinoma in 58, squamous carcinoma in 24, and the others in 12. DNA was extracted from the TBAC samples, and EGFR mutations were analyzed using direct sequencing (exon 19 and exon 21) and Scorpion ARMS method (E746-A750del and L858R). Results: The mutations were detected in 31patients (33%). 13 mutations (14%) (E746-A750del; 6 patients, L858R; 7 patients) were detected by direct sequencing. 27 mutations (29%) (E746-A750del; 16 patients, L858R; 11 patients) were detected by Scorpion ARMS method. Conclusion: EGFR mutations were able to be detected in TBAC samples by both methods. Scorpion ARMS method is more sensitive for the detection of EGFR mutations than direct sequencing. No significant financial relationships to disclose.