Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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New Cancer Technique Facilitates Early Detection

Pet Column for the week of December 31, 2001

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Jennifer Stone
Information Specialist

A detection technique called TRAP (Telomeric Repeat Amplification Protocol) used in the early detection of cancer in humans has found its way in to the realm of veterinary medicine. This new method of cancer detection allows veterinarians to catch cancer earlier, increasing the likelihood of successful treatment.

The test works by detecting the enzyme telomerase, which helps cancer cells reproduce indefinitely. Dr. Barbara Kitchell, a veterinary oncologist at the University of Illinois Veterinary Teaching Hospital in Urbana says, "Telomerase activity seems to be a unique feature of benign tumor cells that have undergone malignant transformation."

Regular cells and cancer cells have some very basic differences. A normal cell has a "cap" called a telomere on the end of its DNA. DNA is a substance found in the nucleus of the cell that contains all of the information about the cell. The "cap" prevents damage of the DNA sequences during mitosis, which is reproduction of the cell by division. The telomere sits on the end of the DNA strand and guards its integrity. After each cell division the telomere erodes a bit until it can no longer protect the cell from errors during cell division (replication). At this point a normal cell will be signaled to stop replicating or will die of apoptosis, which is pre-programmed cell death.

Cancerous cells have the unique characteristic of being "immortal," which means that they do not die when they are supposed to and they have unlimited ability to reproduce themselves. Cancer cells achieve this through several different mechanisms, one of which is the production of an enzyme called telomerase. Telomerase acts by adding on to the end of the telomere that caps the DNA. Because the telomere does not get shorter over time as it normally should, the cell is not triggered to stop replicating. This is one of the reasons that malignant cancer cells keep growing.

Because normal cells do not usually produce the enzyme telomerase, presence of this enzyme can indicate the presence of cancer. Dr. Kitchell says, "Based on our findings to date, we believe this tool may prove to be useful to help us rapidly diagnose malignancies."

In a recent study of telomerase activity in cats, published in the American Journal of Veterinary Research, telomerase activity was present in 29 of 31 malignant tumors and only 1 of 22 benign tumors examined over a two-year period. Dr Kitchell believes that the two malignant tumors were found to be negative of telomerase activity due to errors in tissue processing.

In addition to early detection, this enzyme is also under investigation as a possible tool to use in the future as a target in the treatment of cancer. Dr. Kitchell says, "If the thing proves to be really useful in larger clinical studies, then I would anticipate a snap style ELISA kit for the early detection of cancer could be available at your neighborhood clinic some time in the future."

If you have any questions about cancer in pets, please contact your local veterinarian.