Scientists are developing what could prove to be a highly accurate way of finding cancer hidden in the body: detecting the presence of a protein that makes tumors live forever.
The protein, called telomerase, is the body’s immortality chemical. Ordinarily it disappears after the fetus develops in the womb. But cancer cells produce this substance so they can divide over and over without succumbing to normal aging and death.
About 150 reports on telomerase are being presented at this week’s meeting of the American Association for Cancer Research, up from five or so two years ago.
Researchers described how they are using telomerase to find cancers early, to distinguish them from benign growths, to judge cancer’s lethal potency and to measure its recurrence after treatment.
One study found that telomerase appears to be even more accurate than examining cells under the microscope, now the standard way of judging whether they are cancerous.
Furthermore, at least a dozen pharmaceutical companies are working on drugs to shut down telomerase, starving cancer of something critical to its survival. None of these has entered human testing yet.
“This is one of the most exciting advances in cancer biology to emerge in the last decade,” Dr. Jerry W. Shay of the University of Texas Southwestern Medical Center said Tuesday.
However, it is unclear how far away a practical and reliable test may be.
Dr. Donald S. Coffey of Johns Hopkins University called the telomerase research “a very interesting breakthrough” but cautioned that it must be detected in cancer cells themselves, which are relatively inaccessible and means it cannot be offered as a simple blood test.
In adults, only cancer cells make telomerase, and it can be detected in about 85 percent of tumors. In some major cancer killers, such as lung and breast cancer, telomerase production is turned on even before the cancers begin their dangerous spread.
Over the past two years, a test has emerged that can detect telomerase in samples that contain as few as 10 cancer cells.
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