UCLA scientists have developed a simple and cost-effective blood test that, in early studies in more than 1,000 people, showed promise in detecting multiple cancers, various liver conditions, and organ abnormalities simultaneously.
The new method, called MethylScan, works by analyzing cell-free DNA (cfDNA), tiny fragments of genetic material released into the blood when cells die. Because cells from every organ shed DNA into the bloodstream, cfDNA carries molecular signals that reflect what is happening throughout the body.
The researchers say MethylScan could represent a powerful and more affordable approach to early disease detection and comprehensive health monitoring. “Early detection is crucial,” said research lead Jasmine Zhou, PhD, a professor of pathology and laboratory medicine and investigator at the UCLA Health Jonsson Comprehensive Cancer Center. “Survival rates are far higher when cancers are caught before they spread. If you detect cancer at stage one, outcomes are dramatically better than at stage four.” Zhou is senior author of the team’s published paper in PNAS, titled “Toward the simultaneous detection of multiple diseases with a highly cost-effective cell-free DNA methylome test.”
“When cells die, they do not simply vanish; they leave behind molecular traces, including cell-free DNA (cfDNA) in the blood stream,” the authors wrote. “cfDNA is a mixture of DNA fragments released from various organs, offering valuable insights into the health of these organs.” Zhou added, “Every day, 50 to 70 billion cells in our body die. They don’t just disappear, their DNA goes into the bloodstream. That means we already have information from all our organs circulating in the blood.”
The idea of using blood to detect cancer, sometimes called a liquid biopsy, isn’t new. Some tests already look for mutations in tumor DNA to screen for certain cancers. But those tests often focus on a limited number of genetic changes and can be expensive, in part because they require deep sequencing to detect faint tumor signals.
Instead of searching for mutations, the UCLA team examined DNA methylation, chemical tags attached to DNA that help regulate gene activity. Methylation patterns differ by tissue type and can change when cells become cancerous or diseased. “Unlike an individual’s genome, which remains largely stable across tissues and over time (except for rare somatic mutations), the DNA methylome is tissue-specific and dynamically changes with the tissue’s disease status,” the team continued.
“DNA methylation reflects the health status of a tissue,” said co-corresponding author Wenyuan Li, PhD, a professor of pathology and laboratory medicine at UCLA and co-corresponding author of the study. “It’s a very informative signal.”
The challenge is that most cell-free DNA in the bloodstream doesn’t come from tumors or injured organs. About 80% to 90% originates from normal blood cells. That creates background noise, making it difficult and costly to detect the relatively rare fragments that might signal early cancer. “A major challenge in using the cfDNA methylome for disease detection is the high cost of sequencing,” the team stated. “In healthy individuals, about 85% of cfDNA originates from blood cells, creating substantial background noise that can obscure cfDNA from tumors or diseased organs.” And as the authors further pointed out, “Current cfDNA methylation assays primarily focus on single clinical indications by targeting specific genomic loci.”
For their newly reported research the team built on past work to develop a technique to remove much of the background DNA before sequencing. Using specialized enzymes, they selectively cut away unmethylated DNA fragments that largely come from blood cells. By designing a genome-wide hybridization panel, the captured DNA fragments are enriched for methylated DNA from solid organs, including those that are potentially diseased. “The MethylScan method is a targeted methylation assay that combines Methylation-Sensitive Restriction Enzymes (MSRE) digestion with a custom panel to enrich hypermethylated cfDNA from tissues beyond blood, enabling cost-effective detection of multiple diseases,” they wrote.
By removing the noise, the researchers say they can dramatically reduce the amount of sequencing needed, lowering costs while maintaining sensitivity. Achieving an effective sequencing depth of 300× per sample requires only 5 Gb of data, which would cost less than $20 if the price per gigabase is under $4.
To test the accuracy of MethylScan, the researchers analyzed blood samples from 1,061 people, including patients with liver, lung, ovarian and stomach cancers; individuals with liver diseases such as hepatitis B, hepatitis C, alcohol-related liver disease, and metabolic-associated liver disease; people with benign lung nodules; and healthy participants. Machine learning algorithms were then applied to analyze the complex methylation data.
For multi-cancer detection, the test achieved a high level of overall accuracy. At a specificity of 98%, meaning few false positives, it detected about 63% of cancers across all stages and roughly 55% of early-stage cancers. The test also performed well in liver cancer surveillance among high-risk individuals, including those with liver cirrhosis or HBV, detecting nearly 80% of cases at a specificity of just over 90%, meaning a less than 10% false positive rate.
Beyond simply detecting cancer, the methylation patterns helped identify where in the body a signal was coming from, known as the tissue of origin. “Being able to trace signals back to their source is important because a positive blood test needs to be followed by imaging or other diagnostic procedures directed at the right organ,” said Li.
MethylScan can work like a health radar for the body. By reading DNA signals in the blood, it can tell when specific organs, such as the liver or lungs, are under stress or damaged, even without knowing the disease in advance. The researchers also showed that the blood test could distinguish between different types of liver disease, including viral hepatitis and metabolic-associated liver disease. It correctly classified about 85% of patients, suggesting blood-based DNA testing could reduce the need for invasive liver biopsies.
Although larger prospective trials will be needed to confirm its performance in real-world screening, Zhou said the work represents an important step toward a single, affordable blood assay that can detect a broad spectrum of diseases earlier and more comprehensively than current methods allow.
“Because cfDNA in blood originates from multiple organs, and MethylScan captures a broad spectrum of robust hypermethylation markers, this assay has the potential to detect a variety of diseases, provided that appropriate training cohorts are available,” the investigators stated. “This versatile approach enables affordable, wide-ranging cfDNA tests that can identify various health conditions simultaneously, with the potential to transform early disease detection and health monitoring across diverse clinical settings.
Zhou added, “This study demonstrates that blood-based methylation profiling can deliver clinically meaningful information across multiple diseases. It’s an exciting advancement that brings us closer to realizing the dream of a single assay for universal disease detection.”
