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Blood tests that read chemical marks on fragments of DNA shed by tumours; the marks tell cancer DNA from normal DNA and hint at where the cancer is.
Cancer cells carry characteristic DNA methylation patterns that survive in the cell-free DNA shed into blood. Methylation-based tests use bisulfite or enzymatic conversion followed by targeted sequencing to detect a cancer signal and predict its tissue of origin; the multi-cancer early detection test Galleri works this way, and Guardant's Shield, the first blood test approved by the FDA for colorectal cancer screening in 2024, combines methylation with other cfDNA signals. Methylation also underpins some minimal residual disease assays.
Extract cfDNA from plasma, convert unmethylated cytosines, sequence targeted regions, and classify methylation patterns against reference tumour and normal profiles.
Nothing in the corpus depends on this yet.
Dependencies are what this technology cannot be delivered without: manufacturing steps, instruments, software, upstream methods. See its full chain on the map.
IMBdx's blood test from South Korea, offered at screening centres there, which in a laboratory study detected nine in ten cancers including stage I.
A research blood test that looks for six digestive-system cancers at once and predicts which organ the signal comes from.
GRAIL's blood test that looks for a signal from more than 50 cancers at once; an FDA advisory panel voted in its favour in September 2026, but in the NHS-Galleri randomised trial three yearly tests did not reduce the number of cancers found at a late stage.
Burning Rock's methylation blood test from China for five or six cancers, with Breakthrough designations from the US and Chinese regulators but no approval yet.
Singlera's methylation blood test, tested on stored samples from a Chinese cohort, that reported finding cancers up to four years before they were diagnosed; it has not been confirmed in a prospective study.
Guardant Health's blood test for ten cancers, offered in the United States as an add-on report to its bowel cancer blood test and chosen by the US National Cancer Institute for its first randomised study of such tests.
Gene Solutions' low-cost blood test from Vietnam; in 9,024 people without symptoms about one in two hundred tested positive and four in ten of those had cancer.
This is the first randomised answer to whether a multi-cancer blood test changes outcomes, and for its main question the answer was no: adding the test to NHS care for three years did not lower the number of cancers diagnosed at stage III or IV. The stage IV result is a secondary finding with a confidence interval that touches no effect, and deaths have not yet been reported, so the trial continues to follow participants.
Supports the design choice of most current tests: methylation first, with proteins as an add-on rather than mutations.
These are the numbers GRAIL's US application rests on. Six in ten positive results were cancer and the predicted organ was usually right, but six in ten cancers diagnosed in the year were not flagged, and the study had no control group, so it cannot say whether testing changes outcomes.
It is the only peer-reviewed stage-by-stage figure for the Cancerguard approach, and it describes a development classifier at 98.5% specificity, not the launched test, which Exact Sciences says runs at 97.4% specificity.
For someone offered the test, these are the numbers that describe what a result means in an NHS population: about 1 in 100 tests came back positive each year, between 46 and 58 in 100 positives were cancer, and a negative result left about 1 in 100 with an undetected cancer within the year. The test found between a quarter and a third of all cancers diagnosed in a screening round, and about half to two thirds of the 12 cancer types it was designed to find. Whether finding them this way reduces late-stage diagnoses is the primary question, and this paper says only that the answer was no; the primary-endpoint paper had not appeared on Europe PMC by 23 September 2026.
In people who already have symptoms the test is more often right when positive, because cancer is commoner, but it still misses most stage I cancers, so a negative result cannot cancel an urgent referral.
High early-stage figures at a lower specificity than screening needs; in the prospective K-DETEK study the test was run at 99.7% specificity.
The strongest published evidence for OverC, still from people already diagnosed with cancer rather than a screening population.
Query for this technology: (TITLE:"Cell-free DNA methylation tests" OR ABSTRACT:"Cell-free DNA methylation tests") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Cell-free DNA methylation tests, not a curated reading list.
Shares Multi-cancer early detection test in symptomatic patients referred for cancer investigation in England and Wales (SYMPLIFY): a large-scale, observational cohort study, Evaluation of cell-free DNA approaches for multi-cancer early detection, Sensitive and specific multi-cancer detection and localization using methylation signatures in cell-free DNA, Performance and safety of a multi-cancer early detection test: the PATHFINDER 2 study.
Shares Evaluation of cell-free DNA approaches for multi-cancer early detection, Sensitive and specific multi-cancer detection and localization using methylation signatures in cell-free DNA, CCGA: the Circulating Cell-free Genome Atlas behind the Galleri methylation test, Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set.
Shares Evaluation of cell-free DNA approaches for multi-cancer early detection, Sensitive and specific multi-cancer detection and localization using methylation signatures in cell-free DNA, PATHFINDER 2, NHS-Galleri.
Shares Performance and safety of a multi-cancer early detection test: the PATHFINDER 2 study, PATHFINDER 2, Performance of a multi-cancer early detection test in the randomized controlled NHS-Galleri trial, NHS-Galleri.
Shares Effect of Screening with Multicancer Early-Detection Test on Late-Stage Cancer Diagnosis, PATHFINDER 2, Performance of a multi-cancer early detection test in the randomized controlled NHS-Galleri trial, NHS-Galleri.
Shares Shield MCD (Shield Multi-Cancer Detection), PATHFINDER 2, NHS-Galleri, Galleri.
Shares CancerFind, Multimodal analysis of methylomics and fragmentomics in plasma cell-free DNA for multi-cancer early detection and localization, SPOT-MAS, Evaluation of cell-free DNA approaches for multi-cancer early detection.
Shares Multi-cancer early detection test in symptomatic patients referred for cancer investigation in England and Wales (SYMPLIFY): a large-scale, observational cohort study, Shield MCD (Shield Multi-Cancer Detection), Performance and safety of a multi-cancer early detection test: the PATHFINDER 2 study, CCGA: the Circulating Cell-free Genome Atlas behind the Galleri methylation test.