Genomic analysis of circulating tumour DNA: pushing the limits for cancer applications
1Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK,2Inivata Ltd., Cambridge, UK
Cancer is driven by genomic alterations, and can evolve in response to selective pressures. Sampling of tumour material however is a limiting factor for both diagnostics and research. Circulating tumour DNA can be found in plasma and other body fluids, and with advanced genomic techniques it can be used as an effective source of information for oncology. On one hand, sensitive detection of mutations, rearrangements and copy number changes can be used for genomic characterisation of cancer using non-invasive sampling. Targeted molecular profiling tests of "liquid biopsies" in blood plasma are now entering clinical use, and are emerging as an informative clinical research tool to track response to treatment, cancer progression and emergence of resistance to therapy. Wider-scale analysis can be used to study new drivers and mechanisms of resistance. In parallel, the specificity of genomic alterations makes these excellent markers to quantify cancer dynamics and disease burden. Improved methods and strategies can allow us to stretch the boundaries of analysis to detect smaller amounts of tumour DNA and to obtain more information from limited samples. These can be used to support an expanding range of applications for both earlier and later stage cancers.