Distinguishing Circulating Tumor from Normal Cell-Free DNA

Fragments of circulating DNA from tumors are around 20 to 30 base pairs shorter than those from healthy cells, researchers report.

Written byAlison F. Takemura
| 1 min read

Register for free to listen to this article
Listen with Speechify
0:00
1:00
Share

Untreated glioblastoma WIKIMEDIA, AFIPPieces of tumor DNA circulating in the bloodstream are generally shorter than circulating DNA fragments derived from healthy cells, scientists reported this week (July 18) in PLOS Genetics.

Researchers from the University of Washington and the University of Utah observed the DNA difference by analyzing fragments derived from human glioblastoma and hepatocellular carcinoma cells transplanted in rats. The team observed that the human circulating tumor DNA was typically 134 to 144 base pairs long, while the rat circulating DNA was typically 167 base pairs long.

The scientists were then able to confirm this length difference in people: a cohort of 15 patients with lung cancer compared against nine healthy individuals, GenomeWeb reported.

Human circulating tumor DNA “was overall consistently shorter than the fragment length of normal cell-free DNA,” the authors wrote in their paper.

The findings could help improve cancer diagnosis and treatment prescription using liquid biopsies—a minimally invasive cancer detection method that ...

Interested in reading more?

Become a Member of

The Scientist Logo
Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member? Login Here

Related Topics

Meet the Author

Share
February 2026

A Stubborn Gene, a Failed Experiment, and a New Path

When experiments refuse to cooperate, you try again and again. For Rafael Najmanovich, the setbacks ultimately pushed him in a new direction.

View this Issue
Human-Relevant In Vitro Models Enable Predictive Drug Discovery

Advancing Drug Discovery with Complex Human In Vitro Models

Stemcell Technologies
Redefining Immunology Through Advanced Technologies

Redefining Immunology Through Advanced Technologies

Ensuring Regulatory Compliance in AAV Manufacturing with Analytical Ultracentrifugation

Ensuring Regulatory Compliance in AAV Manufacturing with Analytical Ultracentrifugation

Beckman Coulter Logo
Conceptual multicolored vector image of cancer research, depicting various biomedical approaches to cancer therapy

Maximizing Cancer Research Model Systems

bioxcell

Products

Sino Biological Logo

Sino Biological Pioneers Life Sciences Innovation with High-Quality Bioreagents on Inside Business Today with Bill and Guiliana Rancic

Sino Biological Logo

Sino Biological Expands Research Reagent Portfolio to Support Global Nipah Virus Vaccine and Diagnostic Development

Beckman Coulter

Beckman Coulter Life Sciences Partners with Automata to Accelerate AI-Ready Laboratory Automation

Refeyn logo

Refeyn named in the Sunday Times 100 Tech list of the UK’s fastest-growing technology companies