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17 April 2014 12:48 pm ,
Vol. 344 ,
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Diagnosing Cancer Made Easy
21 March 2000 6:00 pm
Detecting some tumors may become a lot simpler and less invasive in the future, according to a study published in the 17 March issue of Science. Researchers have shown how certain mutations in DNA found in bodily fluids can help doctors detect cancer of the bladder, lung, and neck and head.
The telltale mutations showed up in the mitochondria, the powerhouses within the cell, which each have many copies of a minigenome. Like nuclear DNA, this mitochondrial DNA (mtDNA) can accumulate mutations. Three years ago, researchers found several unique mutations in mtDNA from bowel tumor cells. It's not clear exactly what causes them, or what role they play in cancer. But the finding spurred molecular geneticist David Sidransky and colleagues at the Johns Hopkins University in Baltimore to look for mtDNA mutations that might flag other types of cancer.
The team took tumor cells from 46 patients with cancer of the bladder, head, neck, and lung and sequenced the cells' mtDNA. Comparing the sequences with those from blood samples and healthy tissue from the same patients, they found 39 mutations specific for the tumor cells. Sidransky's team suspected that because cellular debris from the bladder sometimes ends up in urine, they might look for the mtDNA mutation there as well; likewise, mutations from neck and head tumors might show up in saliva, and from lung tumors in lung fluid.
Sure enough, when the researchers analyzed these body fluids, they found the same characteristic mutations as those that turned up in the mitochondria from tumor tissues. Because mitochondria contain so many copies of the same DNA, the mutations were also more abundant than known tumor-associated mutations in nuclear DNA, and thus easier to detect.
The technique may be a useful and patient-friendly addition to the growing arsenal of genetic tests to detect cancer, says Curtis Harris, a molecular epidemiologist with the National Cancer Institute in Bethesda, Maryland.