Common Signature Found in Tumor DNA 5 Types of Cancer (image) NIH/National Human Genome Research Institute Share Print E-Mail Caption The signature results from a chemical modification of DNA called methylation, which can control the expression of genes like a dimmer on a light switch. They hope this finding will spur development of a blood test that can be used to diagnose a variety of cancers at early stages. Credit Darryl Leja, NHGRI Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.