A brief retrospective report on the feasibility of epidermal growth factor receptor and KRAS mutation analysis in transesophageal ultrasound- and endobronchial ultrasound-guided fine needle cytological aspirates.
BACKGROUND
Molecular testing for epidermal growth factor receptor (EGFR) and KRAS mutations is of increasing clinical importance in daily practice. In this study, we aimed to investigate the yield and applicability of molecular testing for KRAS and EGFR mutations in cytologic specimens obtained by EUS or endobronchial ultrasound (EBUS)-guided fine needle aspiration (FNA).


METHODS
We selected all patients with an EUS- or EBUS-guided FNA positive for lung adenocarcinoma from the database of our tertiary care center for endosonography. Direct smears were Giemsa and Papanicolaou stained. The remaining material was processed in cell blocks. Both cell blocks and smears were considered suitable for molecular analysis when >40% of the aspirated cells were tumor cells. All eligible samples were investigated for KRAS and EGFR mutations by polymerase chain reaction followed by direct sequencing.


RESULTS
Four hundred sixty-two patients underwent EUS or EBUS-FNA using 22-gauge needles. In 35 patients, FNA showed lung adenocarcinoma. In eight patients, molecular analysis could not be performed because of insufficient material after routine and immunocytochemistry (n = 3), a low percentage (<40%) of tumor cells (n = 3), or an insufficient DNA quality (n = 2). The average percentage of tumor cells was 73% ± 23%. Molecular analysis could reliably be performed in 27 patients (77%). Mutation analysis showed KRAS and EGFR mutations in tumor samples from 10 (37%) and two (7%) patients, respectively. In one patient, two EGFR mutations (p.Thr790Met and p.Leu858Arg) were detected.


CONCLUSIONS
Molecular analysis for KRAS and EGFR mutations can be performed routinely in cytologic specimens from EUS- and EBUS-guided FNA.
Schuurbiers
Olga C J
OC
Department of Pulmonary Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Looijen-Salamon
Monika G
MG
Ligtenberg
Marjolijn J L
MJ
van der Heijden
Henricus F M
HF
D000230:Adenocarcinoma / Q000175:diagnosis / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000235:genetics; D019160:Endosonography; D066246:ErbB Receptors / Q000235:genetics*; D004947:Esophagus / Q000473:pathology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012189:Retrospective Studies; D055752:Small Cell Lung Carcinoma / Q000175:diagnosis / Q000235:genetics; D018631:ras Proteins / Q000235:genetics*
C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins