Feasibility of DNA and RNA preservation from EBUS-TBNA supernatant for molecular profiling in non-small cell lung cancer.

BackgroundEndobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) is used to diagnose and stage Non-Small Cell Lung Cancer (NSCLC), where the supernatant is discarded.Research questionCan DNA/RNA extracted directly from formaldehyde-preserved EBUS-TBNA supernatant, provide sufficient and reliable molecular profiling in NSCLC?Study design and methodsThis prospective study included patients with advanced NSCLC (stage III-IV) undergoing EBUS-TBNA to compare DNA/RNA quantification, NGS feasibility and molecular findings between the supernatant phase (Sp) and the cell pellet (Cp).ResultsThe median DNA and RNA concentrations were significantly higher in Sp than Cp, with Sp showing 29.9 ng/µL DNA and 52.12 ng/µL RNA versus 9.58 ng/µL and 13.6 ng/µL in Cp (Wilcoxon signed rank test, p = 0.012 and p = 0.005). MP in Cp identified 16 mutations (7 actionable), while Sp detected 19 mutations, including two additional actionable mutations. Concordance between Cp and Sp was 87%, with identical mutations in 13 cases and discrepancies in two cases.ConclusionsSp obtained from EBUS-TBNA is a rich source of tumour DNA and RNA, with high feasibility for NGS. There is strong concordance of NGS results between Cp and Sp, supporting Sp as a complementary/alternative source for molecular profiling in NSCLC, potentially reducing the need for additional biopsies.