Cell-free DNA in the supernatant of pleural effusion can be used to detect driver and resistance mutations, and can guide tyrosine kinase inhibitor treatment decisions.

Molecular profiling of tumours has become the mainstay of diagnostics for metastasised solid malignancies and guides personalised treatment, especially in nonsmall cell lung cancer (NSCLC). In current practice, it is often challenging to obtain sufficient tumour material for reliable molecular analysis. Cell-free DNA (cfDNA) in blood or other bio-sources could present an alternative approach to obtain genetic information from the tumour. In a retrospective cohort we analysed the added value of cfDNA analysis in pleural effusions for molecular profiling. We retrospectively analysed both the supernatant and the cell pellet of 44 pleural effusions sampled from 39 stage IV patients with The driver mutation could be detected in 36 of the 44 pleural effusions by analysis of both the supernatant (35 out of 44 positive) and the cell pellet (31 out of 44 positive). In seven out of 20 pleural effusions from patients with cfDNA in pleural effusion can be used to detect driver mutations as well as resistance mechanisms like

Déclaration de conflit d'intérêts

Conflict of interest: K. Hummelink has nothing to disclose. Conflict of interest: M. Muller has nothing to disclose. Conflict of interest: T.C. Linders has nothing to disclose. Conflict of interest: V. van der Noort has nothing to disclose. Conflict of interest: P.M. Nederlof has nothing to disclose. Conflict of interest: P. Baas has nothing to disclose. Conflict of interest: S. Burgers has nothing to disclose. Conflict of interest: E.F. Smit has nothing to disclose. Conflict of interest: G.A. Meijer reports patents pending on biomarkers and on the diagnosis and prognosis of colorectal cancer, and research collaborations with Exact Sciences and Sysmex in which the companies provide materials, equipment or (sample) analyses. Conflict of interest: M.V. van den Heuvel has nothing to disclose. Conflict of interest: D. van den Broek has nothing to disclose. Conflict of interest: K. Monkhorst reports personal fees from Pfizer to attend ASCO 2016, personal fees from Roche Pharma to attend ASCO WCLC 2017, speaker's fees from Roche Diagnostics and Benecke, and has served on advisory boards for Pfizer, Roche, MSD, AbbVie and BMS, outside the submitted work.