ctDNA and Lung Cancer

The discovery of cell-free DNA (cfDNA) in biofluids such as blood, saliva, urine, and pleural fluid has broadened our understanding of extracellular genomic biology and is enabling a variety of important clinical applications. The promise of clinical utility has fueled efforts both to understand the physiologic underpinnings of cfDNA and to broaden the repertoire of cancer-associated signals being queried. Although the field initially focused primarily on measurement of cancer-associated mutations in cell-free DNA, recent years have seen tremendous progress in the characterization of other cancer-associated DNA features such as methylation, fragment length, nucleosome positioning, and strandedness. These advances are driving the development of diagnostic technologies for treatment selection, therapy monitoring, assessment of minimal residual disease, and early cancer detection. This chapter will review the landscape of cfDNA biology and the scientific and technological advances for the assessment of cfDNA, with a particular focus on non-small cell lung cancer as a clinical model.