Under-$20 Blood Test 'MethylScan' Catches Multiple Cancers in One Draw

Under-$20 Blood Test 'MethylScan' Catches Multiple Cancers in One Draw — and Pinpoints Their Origin

UCLA researchers unveiled MethylScan, a low-cost blood test that reads DNA methylation to detect liver, lung, ovarian and stomach cancers from a single sample — and trace where they started. In early studies it caught 63% of cancers across all stages at 98% specificity, with sequencing costs under $20 per sample.

Key Takeaways

UCLA researchers unveiled MethylScan, a low-cost blood test that reads DNA methylation to detect liver, lung, ovarian and stomach cancers from a single sample — and trace where they started.
In early studies it caught 63% of cancers across all stages at 98% specificity, with sequencing costs under $20 per sample.

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A single, affordable blood draw that screens for several cancers at once — and says where they started — moved a step closer after UCLA scientists unveiled a method called MethylScan in the journal Proceedings of the National Academy of Sciences.

The test works by reading chemical tags on cell-free DNA (cfDNA), tiny fragments of genetic material shed into the bloodstream when cells die. Because cells from every organ release DNA into the blood, cfDNA carries molecular signals from the whole body. "Every day, 50 to 70 billion cells in our body die. They don't just disappear, their DNA goes into the bloodstream," said Dr. Jasmine Zhou, senior author and professor at UCLA Health's Jonsson Comprehensive Cancer Center.

Instead of hunting for cancer-driving mutations — the approach behind many existing liquid biopsies — MethylScan examines DNA methylation, chemical tags that help regulate gene activity and differ by tissue type. The problem: 80% to 90% of cfDNA comes from normal blood cells, drowning out rare tumor signals. The UCLA team stripped away most of that background noise with specialized enzymes, then enriched the remaining DNA for signals from solid organs. That slashes the sequencing needed: a sample can be processed at 300× effective depth with just 5 Gb of data, costing less than $20.

In tests on blood samples from 1,061 people — patients with liver, lung, ovarian and stomach cancers, people with liver diseases, benign lung nodules and healthy participants — MethylScan detected about 63% of cancers across all stages and roughly 55% of early-stage cancers at a specificity of 98%, meaning few false positives. Among high-risk individuals with cirrhosis or hepatitis B, it caught nearly 80% of liver cancers with a false-positive rate below 10%.

Crucially, the methylation patterns also revealed where in the body the signal came from — the tissue of origin — so a positive result can direct imaging to the right organ. The test also distinguished between different types of liver disease about 85% of the time, suggesting it could reduce invasive liver biopsies.

Larger prospective trials are still needed, but the researchers say MethylScan points toward the long-sought goal of a single, affordable assay for broad disease detection — a "health radar" for the body.