More than a hundred different diseases fall under the umbrella term “cancer.” Since it’s not a single illness, there is no one way to spot and treat it. However, that doesn’t mean that scientists aren’t trying. Over the years, there have been various studies on how a single test might be able to screen for multiple types of cancer. The key lies in finding a unique signature or biomarker of cancer – a characteristic that all malignant cells share but healthy cells do not.
The Key Lies In The DNA
Deoxyribonucleic acid or DNA is one such distinct cancer biomarker. Every cell in the human body has this hereditary material, but according to a team of researchers in Australia, cancer DNA takes on a different structure compared to that of normal cells.
This is the premise of a paper that the team published in December 2018 in Nature Communications. They discovered that the DNA of cancer cells has a strange shape and that they also bind tightly to gold nanoparticles. Meanwhile, the DNA from healthy cells do not look or behave in the same way.
Finding A Universal Cancer Biomarker
Professor Matt Trau from the Australian Institute for Bioengineering and Nanotechnology of the University of Queensland as well as lead author on the Nature paper presented the research on March 31 at the yearly meeting of the American Association for Cancer Research.
Trau illustrated how cancer DNA acted using one of his daughter’s toys. The long, colorful train of little plastic pieces joined together represented the DNA. The professor says that DNA would look like that once you take it from the human cell, purify it, and analyze it in the lab.
However, he mentions that it’s not how DNA looks when it’s inside our blood. To demonstrate, he crumbled up the toy. The knotted tangle of DNA crumples up in a different shape when it comes from cancer cells compared to when it comes from healthy cells. This is the focus of the research team’s cancer tests.
Aiming For Accuracy
The scientists were able to achieve a 90 percent accuracy rate in screening cancer in all the types they tested. The test involved gold nanoparticles and took about 10 minutes. All the samples used contained cancer DNA and the test proved to be successful in detecting them 90 percent of the time.
Robert Kovelman also attended the talk. Although he wasn’t part of the study, the senior director at Biological Dynamics, a San Diego-based biotech company, describes the technology that Trau presented as very exciting and something that definitely has potential. However, Kovelman further says that the cancer screening tool is still in its early days and the real challenge is how it’s going to be applied.
Detecting Rare Cancer
Tests that spot cancer at its early stages are nothing new. In fact, screenings for common cancers such as breast and colorectal cancers are already available. The problem lies in testing for rare diseases. Professor Viive Howell from the University of Sydney School of Medicine, who was not part of Trau’s research, mentioned that it’s difficult to have a population screening for a rare type of cancer as it’s simply uneconomical.
And then there’s also the case of diseases that are hard to detect. Howell explains that brain cancer is one such case. Monitoring for symptoms or taking an MRI are essentially the only things you can do to screen it. MRI is expensive and something that most people would do for a screening.
Cancer DNA also rarely exits the brain into the bloodstream since the brain is protected by the blood-brain barrier. This layer prevents most compounds from flowing into or out of the brain. That means it would be a challenge to find bran cancer biomarkers through a blood test.
The methodology has been tested on a variety of cancers, however, none of them were considered “rare” or hard to detect. Howell says she’s not sure if this tool would work for such diseases. But if there was a test that could spot cancer early and doesn’t discriminate against rare illnesses like brain, ovarian, and pancreatic cancer, then that would be groundbreaking.
A Long Way To Go
Trau and his research group have been working on several other potential cancer biomarkers, like those that belong in various protein pathways. He explains that since no marker is perfect, using multiple markers to mitigate its potential weaknesses can be more cost-effective.
Other laboratories around the globe are also working on novel cancer detection tests. Dr. Nadir Arber and Shiran Shapira, scientists at Tel Aviv University in Israel, are researching a blood test that may screen different types of cancer based on proteins found on the outer layer of the cancer cell. Arber believes that there’s still a long way to go in finding a truly universal biomarker. There are many things to consider, such as how cancer cells look in various age groups, genders, and after medication.
Arber also raised the question about inflammation. Apparently, some of the pathways that cause cancer are also involved in inflammation. The problem lies in creating a tool that accurately distinguishes between the two. Other researchers brought a point about age. Some of the structural changes to healthy DNA that happen with age can look the same as what happens to cancer DNA.
The Future of Cancer Detection
Trau’s team has tackled the effects of aging in their study. While there are a few signals that come from the aging process, still about 90 percent seem to arrive from cancerous development. As for inflammation, Trau suspects that it’s not going to be an issue. He says that if it was an inflammation signal, then it would have decreased their precision much earlier.
To bring a universal blood test for cancer to the market, certain criteria need to be met. These include high specificity and sensitivity and full automation with high throughput for medical routine use. In addition, it must be at an affordable cost and provide results in 24 hours.
