One test to diagnose them all: researchers exploit cancers’ unique DNA signature

Researchers at The University of Queensland, Australia have developed a test that could be used to diagnose all cancers. It is based on a unique DNA signature that appears to be common across cancer types.

The test has yet to be conducted on humans, and clinical trials are needed before we know for sure if it can be used in the clinic.

Each cancer type, whether it be breast or bowel cancer, has different genetic and other features. A test that detects one cancer may not work on another. Researchers have long been looking for a commonality among cancers to develop a diagnostic tool that could apply across all types.

Their research, published in the journal Nature Communications, has found that cancer DNA forms a unique structure when placed in water. The structure is the same in DNA from samples of breast, prostate and bowel cancers, as well as lymphoma. The researchers used this discovery to develop a test that can identify the cancerous DNA in less than ten minutes.

Nearly every cell in a person’s body has the same DNA, but studies have found that cancer’s progression causes this DNA to undergo considerable reprogramming.

This change is particularly evident in the distribution pattern of a tiny molecule called a methyl group, which decorates the DNA.

A normal cell DNA’s distinct methyl pattern is crucial to regulating its machinery and maintaining its functions. It is also responsible for turning genes on and off. Altering this pattern is one of the ways cancer cells regulate their own proliferation.

This methyl patterning has been studied before. However, its effect in a solution (such as water) has never been explored. Using transmission electron microscopy (a high-resolution microscope), we saw that cancerous DNA fragments folded into three-dimensional structures in water. These were different to what we saw with normal tissue DNA in the water.

In the lab, gold particles are commonly used to help detect biological molecules (such as DNA). This is because gold can affect molecular behaviour in a way that causes visible colour changes. The University discovered that cancerous DNA has a strong affinity towards gold, which means it strongly binds to the gold particles.

This finding directed the researchers to develop a test that can detect cancerous DNA in blood and tissue. This requires a tiny amount of purified DNA to be mixed with some drops of gold particle solution. By simply observing the colour change, it is possible to identify the cancerous DNA with the naked eye within five minutes.