DNA for diagnosis . . . and other stories

Liquid biopsy—the detection and analysis of tumour derived DNA from peripheral blood—has potential for diagnosis and for guiding treatment. In a large series of patients with non-small cell lung cancer, it also had prognostic significance. Three quarters of patientswith extrapulmonary disease haddetectable amounts of circulating tumourDNA levels, compared with less than half of those with intrapulmonary disease. DNA detection was associated with shorter survival independently of clinical features and tumour volume (Nat Med doi:10.1038/s41591-02202047-z).