The release of cell-free DNA into the bloodstream of patients with various types of cancer, known as circulating tumour DNA (ctDNA), provides a “liquid biopsy” that appears to relate to the characteristics of the source tumours. Such ctDNA has been used as a non-invasive biomarker to detect malignancy, gauge prognosis, predict & follow treatment response, and monitor recurrence. However, current methods have significant limitations in terms of analytical sensitivity (requiring that 1 -5% of DNA is tumour derived) that then impacts on costs.
Next Generation Sequencing (NGS) promises to revolutionise clinical diagnostics, as well as basic research, as the technology has the capacity to generate hundreds of billions of nucleotides of DNA sequence in a single experiment at a fraction of the time (hours vs days) and cost (~£1000 for good coverage) of traditional methods. However, the sensitivity of NGS is limited by the inherent error rate of the sequencer, as incorrectly read bases might be mistaken for true mutant copies. To overcome this limitation, we have developed the ATOM-seq™ (Adaptor Template Oligonucleotide Mediated-sequencing) technology which we believe suitable for detecting rare mutations in blood-borne ctDNA.