Federal scientists have identified a unique “signature” in the DNA of tumor cells in five different types of cancer — a discovery that moves researchers one step closer to developing a non-invasive blood test for cancer that could replace the need for biopsies.

The researchers, form the National Institutes of Health’s National Human Genome Research Institute, also found evidence that this so-called “methylation signature” may be present in many more types of cancer.

It results from a chemical modification of DNA called methylation, which can control the expression of genes “like a dimmer on a light switch,” the scientists noted.

The breakthrough could spur development of a blood test that can be used to diagnose a variety of cancers at early stages, when treatments can be most effective, the researchers reported in The Journal of Molecular Diagnostics.

"Finding a distinctive methylation-based signature is like looking for a spruce tree in a pine forest," said Laura Elnitski, a computational biologist with NIH institute. "It's a technical challenge to identify, but we found an elevated methylation signature around the gene known as ZNF154 that is unique to tumors."

In 2013, Elnitski’s research group discovered a methylation mark (or signature) around ZNF154 in 15 tumor types in 13 different organs — suggesting it is a possible universal cancer biomarker.

"No one in my group slept the night after that discovery," Elnitski said. "We were so excited when we found this candidate biomarker. It's the first of its kind to apply to so many types of cancer."

For new study, the team uncovered telltale methylation markers in colon, lung, breast, stomach, and endometrial cancers.

"Finding the methylation signature was an incredibly arduous and valuable process," said NHGRI Scientific Director Dr. Dan Kastner. "These findings could be an important step in developing a test to identify early cancers through a blood test."

Now, Elnitski’s team plans to screen blood samples from patients with bladder, breast, colon, pancreatic, and prostate cancers. The researchers also plan to test blood samples from women with ovarian cancer to determine if the analysis can lead to improved detection of a recurrence and survival.

"We have laid the groundwork for developing a diagnostic test, which offers the hope of catching cancer earlier and dramatically improving the survival rate of people with many types of cancer," Elnitski said.