Scientists at UCLA have built a cheap blood test that can look for many cancers, liver illnesses, and other organ problems at once. The test works by reading tiny bits of DNA that float in our blood.
How the Test Works
The method, called MethylScan, focuses on cell‑free DNA – small DNA fragments that are released when cells die. Every day, billions of cells break down, and their DNA mixes into the bloodstream, giving a hidden picture of what’s happening inside the body.
Instead of searching for DNA mutations like many other liquid biopsies, MethylScan looks at DNA methylation – tiny chemical tags that tell genes when to turn on or off. Different organs have unique methyl‑tag patterns, and these patterns change when disease appears.
Cleaning Up the Signal
Most DNA in the blood comes from normal blood cells, not from tumors or damaged organs. This extra “background” DNA can hide the important clues. To solve this, the researchers used special enzymes that cut away unmethylated DNA, which mainly originates from healthy blood cells. They also added a panel that grabs the methylated pieces from solid organs.
By removing the noise, the test needs far less DNA sequencing. About 5 gigabytes of data (roughly 300× coverage) can be read for under $20 if sequencing stays cheap.
What the Study Found
The team tested more than 1,000 blood samples. The group included people with liver, lung, ovarian and stomach cancers, various liver diseases, harmless lung nodules, and healthy volunteers.
Using machine‑learning to read the methyl‑tag patterns, MethylScan correctly identified cancer in about 63% of cases while keeping false alarms low (98% specificity). For early‑stage cancers, detection rose to roughly 55%.
When looking at people at high risk for liver cancer, the test spotted about 80% of cancers with a specificity just above 90%.
Finding the Source
MethylScan does more than say “cancer is present.” The methyl‑tag signatures also point to the organ where the signal originates, helping doctors focus follow‑up scans on the right area.
The test could also tell different liver problems apart – such as viral hepatitis versus metabolic‑associated liver disease – with about 85% accuracy, potentially reducing the need for invasive liver biopsies.
Looking Ahead
More large‑scale trials are needed before the test can be used for routine screening. Still, the results show that a single, affordable blood draw might one day give doctors a wide‑angle view of many diseases, catching problems earlier and guiding better care.