Current clinical practice calls for assaying all patients with nonsquamous lung cancer for activating mutations in the EGFR gene and for ALK fusions to identify potential responders to targeted inhibitor therapies. Eventually, though, patients treated with these inhibitors will likely develop treatment resistance. While second- line treatments are available, the molecular mechanism of resistance must be identified and repeat biopsies are necessary. There is much heralding of the potential for liquid biopsies that use tumor-derived cell-free DNA to revolutionize tumor genotyping, particularly for lung cancer where rapid, noninvasive means could improve care. “The absence of reliable prospective data on the use of specific plasma genotyping assays in advanced non–small-cell lung cancer has left key aspects of its utility largely undefined and slowed its uptake as a tool for clinical care in patients with both newly diagnosed NSCLC and EGFR acquired resistance,” writes Adrian Sacher, M.D., in an April 7 study published in JAMA Oncology. The results from this study, the first prospective study of plasma droplet digital polymerase chain reaction (ddPCR), shows that liquid biopsy technology can detect EGFR and KRAS mutations rapidly with high specificity. The authors say the assay is ready to be used for clinical decision making […]