The development of liquid biopsies (LB) has changed substantially the care of patients with solid cancers, in particular late stage lung cancer patients . Addition of LB to management of advanced lung cancer can have a strong impact at three different levels: (i) for the initial detection of actionable oncogenic drivers; (ii) for the identification of resistance mutations in patients relapsing on targeted therapies; and (iii) for the monitoring of the response to therapy and the prediction of the clinical outcome . Within the context of targeted therapeutics, the question arises of whether to use LB on a daily basis to evaluate the presence of rearrangements or mutations in ALK and to propose this approach instead of an analysis made from tissue and/or cytological samples.