We have news! Uniting medical and surgical oncology has had a tremendous impact on our case management ability. Each case benefits from a therapy plan that has been discussed and decided by the team.
Several clinical trials will start soon. Be on the look out for official clinical trial announcements.
Feel free to call us for consultations or visit the Cancer Care Clinic if you are in the neighborhood. We want to provide the best service we can to referring practitioners, so please send your comments and suggestions on how we can serve you better.
Barbara Kitchell, DVM, PhD, DACVIM
Assistant Professor of Medicine
Cancer Care Clinic
University of Illinois
Veterinary Medicine Teaching Hospital
1008 West Hazelwood
Urbana, IL 61802
phone: 217/333-3900; fax: 217/244-9554
By Casey Cadile, Barbara E. Kitchell, Elizabeth Hetler, and Marie
Eve Nadeau
Telomerase is a cellular reverse transcriptase that acts to prevent normal senescence and cell death. All chromosomes have at both ends long stretches of hexanucleotide (TTAGGG) repeats, which are called telomeres. These regions serve to protect the integrity of the coding DNA by shielding it from degradation and recombination. With each round of cell division, the 3' end of the telomeres shortens by several base pairs due to the inability of DNA polymerase to synthesize DNA in a 3' to 5' direction.
In most normal cells (with the exception of germline and some stem cells) after a finite number of cell divisions, the telomeres erode sufficiently to expose the coding DNA to damage, at which point the cell undergoes apoptosis (programmed cell death). For this reason, telomeres serve as a "mitotic clock" to determine the life span of the individual.
The telomerase enzyme uses an RNA template to add tandem TTAGGG repeats onto the ends of telomeres, thus offsetting their shortening. Telomerase therefore extends the replicative capacity and life span of the cell. It is active during fetal development, but is shut down in adult somatic cells. Because telomerase confers cellular immortality, it has been implicated as a critical event in the malignant transformation of cells.
Previous investigation by our laboratory into the role of telomerase in canine cells showed that the TRAPezeTM assay (Oncor, MD) for telomerase activity detected malignant cells with 92 percent sensitivity and 86 percent specificity. We recently initiated a similar study on 46 feline samples and found 30/32 malignant samples and 1/14 benign tumor or normal samples to be telomerase positive.
The TRAPezeTM assay is undergoing its final investigations. We hope to use this assay as a diagnostic tool to support conventional methods of identifying neoplastic cells, either in fluid or in masses, and to facilitate the early detection of malignant processes. We also hope that the significant activation of this enzyme in feline and canine neoplasia will enable us to use this as a target for new therapies.
Illinois Veterinary Bulletin Volume 7, Number 1, April 1999