New cancer test may be as easy as a home-use pregnancy test
Early detection of certain types of cancer may eventually become as easy as taking a home pregnancy test. That’s the prediction of researchers who are developing a non-invasive early diagnostic test for gastric cancer that would not require a pathologist to assess a tissue specimen. Instead, this test detects biomarkers in the patient’s urine.
Surgical pathologists will recognize the potential of this discovery to create new tools for diagnosing cancer at earlier stages—and without the need to collect a tissue specimen. For clinical laboratories, the possibility of a urine-based test that could accurately detect different cancers would make it possible for them to offer diagnostic assays based on this technology to office-based physicians.
This research is being conducted by scientists at the University of Georgia (UGA). A team of researchers there identified, for the first time, that certain proteins excreted in urine can indicate the presence of gastric cancer. Their findings were published by the journal PloS One.
The protein, endothelial lipase, was identified by lead researcher Ying Xu, Ph.D., along with colleagues, Celine Hong, Juan Cui and David Puett of the Institute of Bioinformatics. They determined that this protein differs significantly in its abundance in urine samples of stomach cancer patients versus healthy people.
When certain proteins are abnormally abundant in diseased tissues, they can be excreted into urine. This insight is a key breakthrough in cancer detection, according to Xu. He was quoted in the press release about these findings. The classification system developed by Xu and the research team was more than 80% accurate when it assessed samples from already known excretory and non-excretory proteins.
Xu and his colleagues initially focused their research on stomach cancer because it is the number two cancer killer in the world. “We hope that with further study, the detection of abnormally abundant proteins in urine will lead to diagnosis of many types of cancer and other diseases,” noted Xu in the press release. He is the Regents-Georgia Research Alliance Eminent Scholar of Bioinformatics and Computational Biology, UGA Franklin College of Arts and Sciences.
The researchers initiated the study with a set of 1,500 proteins known to be excreted in urine. Next, they identified a list of features that distinguish these proteins from proteins that are not excreted into urine.
It was these distinguishing features that they used to develop a classification system that could predict which proteins in cancerous tissues are excreted into urine. The research team then used postage stamp-sized microarrays containing nearly 20,000 human genes to identify which proteins were more abundant in the urine from individuals with cancerous versus non-cancerous tissues.
Current procedures for diagnosing gastric cancer, such as endoscopy, are invasive and uncomfortable for patients. Many people avoid them for these reasons. Were this technology to result in a new non-invasive test, even though it is only 80% sensitive, it would encourage more at-risk patients to seek a more comprehensive exam, the release stated. “A person could go get a urine test, and if the marker protein is present, then they are generally stomach-cancer free,” said Xu. “If the protein is not present, we might suggest that they get their stomach checked.”
Now that the researchers have identified a protein marker, Xu indicated, development of a method where urine can change the color of a piece of paper to indicate the presence or absence of the protein should be possible. It would work in a similar way to home pregnancy tests, UGA said. Xu and his team hope to find multiple protein markers for each cancer to increase the accuracy of the test.
Because tissue specimens are invasive, there are many research projects underway that have the goal of using blood, urine, saliva, and even breath as specimens that can be used to accurately diagnose cancer and other diseases. Xu and his research team at UGA plan to continue their research into using the measurements of certain proteins in urine could be a useful tool in screening individuals for specific types of cancers.
—Pamela Scherer McLeod