EGFR and lung cancer: So far, the concept of liquid biopsy has expanded from blood‐based resources to urine, saliva, effusion, cerebrospinal fluid and other body fluid, which acts as a simple, fast and cost efficient alternative for monitoring of disease status, or response to treatment in multiple malignancies, including lung cancer.14, 15, 16, 17, 18, 19, 20 A milestone is the approval for Cobas EGFR Mutation Test v2 (cobas, Roche Diagnostic US, Indianapolis, IN, USA) by the United States Food and Drug Administration (US FDA) in 2016.