Supplementary Material for: Molecular Nodal Staging Using miRNA Expression in Lung Cancer Patients by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration

Background: The limited negative predictive value of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has often been discussed. Objective: The aim of this study was to identify a highly sensitive molecular biomarker for lymph node staging by EBUS-TBNA. Methods: Five microRNAs (miRNAs) (miR-200a, miR-200b, miR-200c, miR-141, and let-7e) were selected as biomarker candidates for the detection of nodal metastasis in a miRNA expression analysis. After having established a cutoff level of expression for each marker to differentiate malignant from benign lymph nodes among surgically dissected lymph nodes, the cutoff level was applied to snap-frozen EBUS-TBNA samples. Archived formalin-fixed paraffin- embedded (FFPE) samples rebiopsied by EBUS-TBNA after induction chemoradiotherapy were also analyzed. Results: The expression of all candidate miRNAs was significantly higher in metastatic lymph nodes than in benign ones (p Conclusions: miR-200c can be used as a highly sensitive molecular staging biomarker that will enhance nodal staging of lung cancer.