Diagnostic Urine Test Developed for Gastric Cancer

The noninvasive test has identified certain proteins that are indicative of gastric cancer and the detection of abnormally abundant proteins in urine will lead to diagnosis of many types of cancer and other diseases.

Scientists at the University of Georgia, (Athens, GA, USA), began by studying a set of 1,500 proteins known to be excreted in urine and identified a list of features that distinguish them from proteins that are not excreted into urine. Identifying these distinguishing features allowed them to develop a classification system that could predict which proteins in cancerous tissues are excreted into urine. They used microarrays-chips that contain nearly 20,000 human genes to identify which proteins varied in abundance in the cancerous versus noncancerous tissues.

The investigators then identified proteins corresponding to those genes that appeared at significantly different levels in the cancer and noncancer samples. From there, they were able to determine which of the abnormally abundant proteins were secreted into the blood and then excreted in urine using the classification method they developed. They identified a protein called endothelial lipase that differed significantly in its abundance in urine samples of stomach cancer patients versus healthy people. Of the 21 urine samples of healthy people, only two did not have the protein. In the 21 urine samples of stomach cancer patients, only one sample was considered to have a relatively high level of the protein and the levels in the rest were low or absent. The study found that the classification system was more than 80% accurate when using samples from already known excretory and nonexcretory proteins. Although the test is not yet 100% accurate, it can lead at-risk patients to seek a more comprehensive examination.

Ying Xu, PhD, lead author of the study, said, "We should be able to develop a method where urine can change the color of a piece of paper to indicate the presence or absence of the protein, similar to the way a home pregnancy test works. A person could go get a urine test, and if the marker protein is present, then they are generally stomach-cancer free. If the protein is not present, we might suggest that they get their stomach checked." The study was published on February 18, 2011, in the online journal Public Library of Science One.

Related Links:
University of Georgia