Current status and perspective of EBUS-TBNA.

In 2002, a new bronchoscope equipped with a convex type ultrasound probe on the tip was introduced into clinical practice. This convex probe endobronchial ultrasound (CP-EBUS) provides a long axis image of surrounding structures of the major airway. The CP-EBUS combined with a dedicated biopsy needle allows real-time endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of mediastinal and hilar lymph nodes. Samples obtained from EBUS-TBNA can be used for pathological diagnosis including immunohistochemistry. EBUS-TBNA is now being performed worldwide for several indications including mediastinal staging, mediastinal pathology and for benign diseases. For mediastinal staging in lung cancer, the diagnostic yield of EBUS-TBNA is comparable to surgical staging in patients with enlarged lymph nodes. In addition, EBUS-TBNA can be used for molecular analysis of tumor cells obtained during the procedure. DNA mutation testing using EBUS-TBNA samples was first reported in 2007 for a chondrosarcoma case. Also, isolated DNA from EBUS-TBNA samples was applied for epidermal growth factor receptor mutation testing and aberrant methylation analysis in patients with lung cancer. RNA was also isolated from properly stored EBUS-TBNA samples and used for gene expression research and aberrant fusion gene detection in lung cancer patients. Optimization of tissue banking methods of EBUS-TBNA specimens was also investigated. Currently, EBUS-TBNA samples can be used for comprehensive mRNA and miRNA expression analysis. EBUS-TBNA will become an important modality for bronchoscopists in the era of personalized medicine in lung cancer.