ALK and cancer: In recent years, nucleic acid-based liquid biopsy for monitoring cancer has attracted much attention.32 For example, cell-free DNA (cfDNA) in the plasma of cancer patients contains tumor-derived DNA sequences, which can be used as biomarkers for the early detection of cancer, guiding treatment, and monitoring drug resistance.33 In 2016, ExoDx Lung (ALK), the world’s first exosomal oncology diagnostic test, was launched.