Could we soon be able to detect cancer in 10 minutes? | Science | The GuardianLooking for ctDNA has become a viable proposition in recent years because of improvements in DNA sequencing technologies that make it possible to scan fragments and find those few with alterations that may indicate cancer. While other blood-based biomarkers are being investigated, the advantage of ctDNA is that, because it has a direct link to the tumour, it can be very specific at identifying cancer. For that reason, ctDNA is also showing promise as a way to profile and monitor advanced stage cancers, a “liquid biopsy”. Early detection is a harder problem. Early on, when the tumour is small, there is not as much ctDNA to detect. The women Illumina identified as having cancer were all late, not early stage.