|
|
|
Osteosarcoma in the Irish Wolfhound Osteosarcoma is the most common bone cancer of dogs. It is primarily a disease of middle-aged and older dogs, estimated to affect over 8000 animals per year in the United States. The tumour is extremely malignant and for greater than 90% of affected animals, which do not receive chemotherapy following limb amputation, the cancer will spread (usually to the lungs) within 1 year of amputation. However, 40-60% of dogs that receive chemotherapy following limb amputation survive for 12 months, and indeed half of these survive long term. Osteosarcoma in the Irish Wolfhound Canine osteosarcoma is associated with increasing height (and weight) and therefore the highest incidence is in large and giant breeds. However, some families within these breeds are particularly susceptible, suggesting an inherited predisposition. An American Kennel Club survey (2004) of the most frequent 10 diseases of 78 dog breeds, diagnosed at veterinary teaching hospitals over a 30 year period, demonstrated that the risk of an Irish Wolfhound developing an osteosarcoma was 27.5 times the risk of all other breeds combined. "Predisposition" to developing cancer is thought to arise because of the existence of hereditary (passed on from one generation to the next) gene mutations. These are defects (present in all cells of the body) in some of the specific segments of chromosomes, which contain the information that tells cells what to do and when to do it. In themselves, these defects are insufficient to cause cancer. However, for individuals carrying such "predisposing mutations", the rare events (for example, mistakes in replication of the chromosomes, or exposure to cancer-causing agents, such as tar in tobacco smoke and ultraviolet radiation from the sun) that can cause a spontaneous gene mutation in a single cell in the body are more likely to lead to cancer. The inherited susceptibility to cancer probably results from the combined effects of many hereditary gene mutations, each of which confers a low to moderate increase in risk. The risk of developing a cancer is thought to increase according to the number of altered genes inherited. We are seeking to identify the genes that, when mutated, are associated with the increased risk of Wolfhounds developing osteosarcomas. Since this breed develops this cancer more often than other breeds, the gene mutations that confer the increased risk of developing osteosarcoma will be more common than in other breeds, and thus easier to identify. Future work would aim to investigate whether the same gene mutations conferred susceptibility to developing osteosarcoma upon other breeds. In the long term, we hope that the research will lead to the development of tests to identify dogs that carry the gene mutations conferring an increased risk, allowing breeders to take this into consideration in their breeding programmes. A realistic objective would be to attempt to reduce the incidence of dogs affected with osteosarcoma. Identification of "osteosarcoma susceptibility genes" will also improve our understanding of how these tumours develop, thereby ultimately assisting the development of new therapies. To perform the study we need to collect samples from large numbers of Wolfhounds that have osteosarcoma (or have had osteosarcoma), and Wolfhounds that do not have cancer. Once we have a substantial number of samples, we can apply for funding to undertake the research to identify the osteosarcoma susceptibility genes contained in the chromosomes (which are made of DNA). DNA can be isolated from cells collected either from the inside of a dog’s cheek, or preferably from a small volume of blood. Since blood sampling is an invasive procedure we only ask dog owners to save surplus blood from that collected by a vet as part of a general health check, or for another medical reason. We are also seeking the approval of breed clubs to attend Championship Shows with an Animal Health Trust vet in order to collect blood samples from the dogs of consenting owners. On such occasions, blood samples are collected from a dog’s leg, from which hair does not need to be removed, and the vet does not attempt to collect blood from dogs that resist. Submitting cheek swabs or blood samples If you would like to request cheek swab kits, with which to collect cheek swabs, please contact Dr Mike Starkey (E-mail: mike.starkey@aht.org.uk). If your vet is able to save blood that is surplus to that collected for a medical reason, please save up to 5ml of whole blood in an EDTA tube. If you submit a blood sample it will be necessary to complete a "Blood sample consent form" for each sample submitted. Please send blood samples and signed consent forms to: Dr Mike Starkey, Centre for Preventive Medicine, Animal Health Trust, Kentford, Newmarket, Suffolk, CB8 7UU, UK. The "Blood sample consent form" is available online in PDF format. You must have Adobe Acrobat Reader installed on your computer to view this form. If you do not have Adobe Acrobat Reader, you can download a free copy from the Adobe website. Left click the link below to open the form in your browser. Right click the link to save the form to your own computer. If you send a blood sample from a country that does not belong to the European Union, send the sample in a package labelled "Animal Pathogen - importation authorised by licence number AHZ/2026A/2004/2 issued under the Importation of Animal Pathogens Order 1980". Unfortunately, we are unable to reimburse you for the cost of sending samples, but we greatly appreciate your invaluable assistance with our proposed important research study. If you have any questions, or would like further details about the proposed study, please contact Dr Mike Starkey (E-mail: mike.starkey@aht.org.uk). Copyright
© 2006 Dr Mike Starkey, The Animal Health Trust, All Rights Reserved. |