by Leslie A. Lyons, PhD
Associate Professor, Department of Population Health & Reproduction,
School of Veterinary Medicine University of California

Lymphomas account for nearly one third of all cancers in domesticated cats, with the most common causes being age and viral exposure, specifically to Feline Leukemia Virus (FeLV).

Current veterinary medicine has reduced the prevalence of FeLV in domesticated cats through effective vaccination; however, the incidence of lymphoma has not similarly decreased. Over the last decade the incidence of viral-negative lymphoma has increased by 2-fold, with especial susceptibility in specific breeds, suggesting alternative causes for the disease, such as a genetic susceptibility.

Particular notice has been made concerning an early-onset form of lymphoma developing consistently within the mediastinum, chest cavity,and occurring at a high incidence in Siamese and Oriental type cats from Australia, Europe and the USA. Breed and age specificity and consistent clinical presentation suggest heritability of this form of lymphoma.

A breeding colony is being used by the feline genetics laboratory of Dr. Leslie Lyons, PhD at the University of California,Davis, School of Veterinary Medicine to test the mode of inheritance and provide working pedigrees for statistical analysis on Siamese/Oriental type lymphoma. Current research is focused on defining the pathological properties and genetic abnormalities of malignant cells from mediastinal tumors. Genetic abnormalities may point to an underlying heritable mutation at fault for the development of mediastinal lymphoma in FeLV-negative cats.

The overall goals of identifying the causative genetic mutation in this particular heritable cancer are to create a genetic test to identify carriers of the mutation, thereby enabling breeders to eradicate propagation of this disease, and benefit the advancement of more cancer-specific treatments. Better treatments could not only improve life, but potentially lead to the development of an effective cure.

Breeders can assist the research efforts in a variety of ways.

The identification of afflicted cats is highly important. The onset of the cancer is very rapid and cats will often present by "mouth breathing",regurgitation, loss of weight, and difficulty breathing. Aggressive chemotherapy needs to be immediately administered for the cat's short term survival. Afflicted cats will generally not survive this cancer. Afflicted cats, their parents and or offspring can be donated to UC Davis to characterize the tumor and to develop a breeding program that will evaluate the inheritance pattern and penetrance of the disease.

Breeders may also offer pedigree information and or blood samples of afflicted cats and their relatives or of unrelated cats as normal controls for the project. Basically, all Oriental and Siamese breeders can contribute in some positive manner to the project! We hope that we have the same success with this project as we have for PKD and genetic tests for solid,points, sepia, albino, chocolate, and cinnamon.

Please feel free to contact Dr. Lyons with questions, comments and concerns regarding the project. For more information go to:

Website: http://www.vetmed.ucdavis.edu/PHR/LyonsDen/

Lab E-mail: felinegenome@ucdavis.edu

E-mail: lalyons@ucdavis.edu

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