Genomic signature could lead to new early-detection cancer test

Having successfully identified a DNA methylation signature in five different cancers, the researchers hope that their work may lead to a new blood test for spotting cancers early(Credit: NIH)

Detecting cancer when it's still in the early stages of development is a difficult task, but an extremely important one, with the chances of effective treatment being much higher the quicker it's caught. Now, a team of researchers from the National Institute of Health (NIH) has identified a signature of tumor DNA that occurs, and is detectable, in five different cancers – a discovery that could lead to a simple early detection blood test.

The work focuses on a chemical modification of DNA known as methylation – a term used to describe the action of molecules, known as methyl groups, adhering to DNA and decreasing the activity of certain genes.

In the case of the study, the researchers were able to detect an elevated methylation signature in a gene known as ZNF154, which is only found in tumors. The original discovery was made in 2013, with the team finding the ZNF154 methylation signature in 15 different types of tumor is 13 different organs.

In the knowledge that the genomic signature could be used as universal cancer biomarker, the team then set to work determining just how effective it could be for early detection. First, the researchers restricted their work to five different cancers, conducted detailed testing on colon, lung, breast, stomach and endometrial cancers to further confirm the presence of the genomic signature.

They then used a specially-developed computer program to look for the marker in the DNA of people with and without cancer, with the goal of pinpointing just how much of the tumor DNA needed to be present in a blood sample for successful detection of the cancer to occur.

The results were very positive, showing that even when the amount of methylated molecules present was reduced by 99 percent, the program with still able to detect the cancer-identifying signature in a sample.

Despite the apparent usefulness of the marker, the connection between the tumors and elevated DNA methylation is not yet understood, though it's thought that it might be a symptom of the disease's disruption of normal cell processes. Furthermore, the researchers aren't even aware of what the gene ZNF154 actually does.

Despite those mysteries, the findings could lead to significantly less intrusive early detection tests for numerous cancers, removing the need for screening techniques such as mammograms and colonoscopies. In the long run, the genomic signature may have a big impact on treatment, with doctors one day being able to use a simple blood test to identify early cancers.

"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," said study lead Dr. Laura Elnitski.

The team plans to continue its work, validating the effectiveness of the detection method using blood samples from patients with breast, colon, bladder, prostate, pancreatic and ovarian cancers.

The research was published in The Journal of Molecular Diagnostics.

Source: NIH

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