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

[BACKGROUND] Endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) is used to diagnose and stage Non-Small Cell Lung Cancer (NSCLC), where the supernatant is discarded.

[RESEARCH QUESTION] Can DNA/RNA extracted directly from formaldehyde-preserved EBUS-TBNA supernatant, provide sufficient and reliable molecular profiling in NSCLC?

[STUDY DESIGN AND METHODS] This 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).

[RESULTS] The 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,  = 0.012 and  = 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.

[CONCLUSIONS] Sp 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.