Key Points
• Conclusion/Relevance: “Together, this is the first study showing that ctDNA analysis on supernatant PE could be used for therapy response monitoring. Due to a higher ctDNA concentration and fractional abundance, PE could even be superior to plasma for more sensitive mutation detection, resulting in a more reliable representation of the disease status. It is therefore proposed that supernatant PE, complementing plasma and tissue, could be used for mutation analysis to guide therapy selection and to monitor disease status.”
• Researchers collected paired PE and plasma samples from lung cancer patients before the start of therapy (N = 2) and from EGFR positive patients during therapy (N = 3). Using droplet digital PCR, they then tested supernatant PE and plasma for mutations in EGFR, KRAS, and BRAF.
• The PE of two patients with suspected lung cancer demonstrated a KRAS mutation with a 5- and 8-fold higher fractional abundance (FA) vs plasma. The EGFR L858R and T790M mutations were detected in PE in three patients with progressive disease during therapy.
• “Tissue genotyping remains the gold standard for targeted therapy selection. However, if this material is insufficient for mutation analysis, alternative sources should be considered. While both plasma and supernatant PE are shown to be good additional sources for mutation analysis, also bronchial lavage fluid has the potential to be an appropriate source,” wrote the authors.