Researchers develop non-invasive early diagnostic test for gastric cancer

April 27, 2011 by Kirk McAlpin

(Medical Xpress) -- Early detection of cancer may eventually become as easy as taking a home pregnancy test, according to new University of Georgia research.

Two studies recently published in the journal identified for the first time that certain proteins excreted in urine can indicate the presence of gastric cancer.

The researchers initially studied 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 Allianceeminent scholar of bioinformatics and computational biologyin the UGA 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 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 says 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, said Xu. Current procedures such as endoscopy are invasive, uncomfortable and may be avoided by many people. “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.”

The researchers 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.

Xu and his colleagues then used microarrays—chips that are about the size of a stamp that contain nearly twenty thousand human genes—to identify which proteins varied in abundance in the cancerous versus non-cancerous tissues. Messenger RNA (mRNA) molecules extracted from the sample tissues are converted to complementary DNAs (cDNAs) and hybridize with their complement genes on the microarray and light up as spots when the corresponding mRNAs are abundant. The researchers then identified proteins corresponding to those genes that appeared at significantly different levels in the cancer and non-cancer samples. From there, the researchers 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.

The UGA researchers work in conjunction with a team of researchers led by Fan Li of Jilin University in China, where Xu spends two months a year working with medical doctors and researchers on sample collection and carrying out microarray experiments. This long-term collaboration has led to the establishment of the Jilin University/University of Georgia Joint Research Center for Systems Biology. The researchers are currently collecting tissues from patients with different types of cancer to identify more protein markers that can be detected in .

Related Stories

Recommended for you

Vitamin C may encourage blood cancer stem cells to die

August 17, 2017
Vitamin C may "tell" faulty stem cells in the bone marrow to mature and die normally, instead of multiplying to cause blood cancers. This is the finding of a study led by researchers from Perlmutter Cancer Center at NYU Langone ...

Outdoor light at night linked with increased breast cancer risk in women

August 17, 2017
Women who live in areas with higher levels of outdoor light at night may be at higher risk for breast cancer than those living in areas with lower levels, according to a large long-term study from Harvard T.H. Chan School ...

Scientists develop novel immunotherapy technology for prostate cancer

August 17, 2017
A study led by scientists at The Wistar Institute describes a novel immunotherapeutic strategy for the treatment of cancer based on the use of synthetic DNA to directly encode protective antibodies against a cancer specific ...

Scientists develop blood test that spots tumor-derived DNA in people with early-stage cancers

August 16, 2017
In a bid to detect cancers early and in a noninvasive way, scientists at the Johns Hopkins Kimmel Cancer Center report they have developed a test that spots tiny amounts of cancer-specific DNA in blood and have used it to ...

Toxic formaldehyde is produced inside our own cells, scientists discover

August 16, 2017
New research has revealed that some of the toxin formaldehyde in our bodies does not come from our environment - it is a by-product of an essential reaction inside our own cells. This could provide new targets for developing ...

Cell cycle-blocking drugs can shrink tumors by enlisting immune system in attack on cancer

August 16, 2017
In the brief time that drugs known as CDK4/6 inhibitors have been approved for the treatment of metastatic breast cancer, doctors have made a startling observation: in certain patients, the drugs—designed to halt cancer ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.