Early detection of cancer may eventually become as easy as taking a home pregnancy test, according to new UGA research.
Two studies recently published in the journal PloS ONE identified for the first time that certain proteins excreted in urine can indicate the presence of gastric cancer.
The researchers initially studied stomach cancer because it is the number two cancer killer in the world. They 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, said Ying Xu, lead author of the study and Regents-Georgia Research Alliance Eminent Scholar of Bioinformatics and Computational Biology in in the Franklin College of Arts and Sciences.
“In theory, the methodology that we developed should be applicable to other cancers,” said Xu, who also is a professor of biochemistry and molecular biology and director of the UGA Institute of Bioinformatics.
Xu and his colleagues, Celine Hong, Juan Cui and David Puett of the Institute of Bioinformatics, identified a protein called endothelial lipase that differed significantly in its abundance in urine samples of stomach cancer patients versus healthy people. Xu said the computational capability presented in the study for predicting which of the abnormally abundant proteins in diseased tissues can be excreted into urine is a key breakthrough in cancer detection. Using samples from already known excretory and non-excretory proteins, the study found that the classification system was more than 80 percent accurate.
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; levels in the rest were low or absent.
“We are suggesting from this relatively small urine sample set that healthy people should have this protein in their urine,” Xu said.
The researchers are currently working on a larger urine sample set of 200 gastric cancer patients and 200 healthy people.
“If the EL protein still has the 10 to 15 percent miscalculation rate as with the 21 versus 21 samples, I think we have found a good diagnostic marker for stomach cancer and potentially other cancers,” said Xu.
Now that the researchers have identified a protein marker, Xu said they 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. The researchers hope to find multiple protein markers for each cancer to increase the accuracy of the test.
Although the test is not yet 100 percent accurate, it can lead at-risk patients to seek a more comprehensive exam, according to Xu.
“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.”