Scientists are developing a test that, for the first time, is allowing them to monitor urine for chemical indicators of cancer. It is hoped the test may one day allow early screening, even telling patients what type of cancer they have and its stage of advancement. The researchers say treatment progress might be monitored with the same test.
The highly sensitive technique will be detailed in the April 1 print edition of the peer- reviewed journal Analytical Chemistry, published by the American Chemical Society (ACS), the world's largest scientific society. ACS Web publication of this paper occurred on Feb. 20.
The test looks for derivatives of a class of heterocyclic chemical compounds called pteridines. Pteridine derivatives play important roles in normal cell metabolism, such as mediating the action of crucial enzymes and helping to synthesize some vitamins, according to author Yinfa Ma, Ph.D., of Truman State University in Kirksville, Mo. But Ma, who collaborated on this study with scientists from the Chinese Academy of Sciences, says that malignant tumors appear to "greatly disturb the biosynthesis and metabolism of pteridines." He wanted to see if he could detect, and make sense of, those changes.
Ma analyzed the amounts of eight different pteridine derivatives in cancer patients' urine and found that "each type of tumor shows its own pattern in changes of pteridine concentrations." This suggests it may be possible to diagnose a particular cancer by looking at a person's urine sample.
Although the metabolic importance of pteridines has been known for decades, Ma says their mechanisms are not fully understood because of difficulties in determining their levels. He claims current quantification methods are too time-consuming, not cost effective, and provide poor separation of similarly structured pteridine derivatives. Ma's group tested urine samples by first separating derivatives with high-performance capillary electrophoresis, then quantifying the minute amounts by laser-induced fluorescence detection.
"The investigation on normal control and various cancer patients showed that there existed a significant difference in pteridine concentrations among the two groups," Ma states, "which indicated that pteridine level may be an important factor for the diagnosis of cancer."
The researchers now plan to carefully study tumors one by one to develop databases and try to determine each cancer's unique pteridine signatures. Ma cautions that the current paper is a preliminary study, adding that while "more data are needed to reach a more solid conclusion about whether the pteridine levels are of diagnostic value, our method does provide a convenient method for further investigation."
A nonprofit organization with a membership of nearly 159,000 chemists and chemical engineers, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.
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