TRANSITIONAL CELL CARCINOMAS IN SCOTTISH TERRIERS
by Dr M Starkey, Animal Health Trust

“Transitional cell carcinoma (TCC) is the most common cancer of the urinary bladder in dogs. It usually arises in the lower neck of the bladder, where it is extremely difficult to remove by surgery, and it causes a partial or complete obstruction to urination. It is an aggressive disease, and in about half of the dogs affected the cancer spreads to local lymph nodes and potentially to other parts of the body. A 2005 Scottish Terrier Club of America report (http://www.stca.biz/index.php?option=com_content&view=article&id=585:bladder-cancer-study-final-report-what-every-scottie-owner-needs-to-know&catid=330:bladder-cancer&Itemid=100) on this cancer in Scottish Terriers refers to research conducted at North American veterinary teaching hospitals that suggested 'a genetic predisposition to TCC in terriers and primarily in Scottish Terriers'. On the basis of this research, in 2010 the American Kennel Club - Charitable Health Foundation funded a further study (by researchers at Purdue University and the National Human Genome Research Institute in the United States) to identify inherited genetic risk factors for TCC of the bladder in Scottish Terriers, West Highland White Terriers, and Shetland Sheepdogs. The research study proceeded for 2 years, and the United States (US) researchers report (http://www.stca.biz/index.php?option=com_content&view=article&id=263:health-trust-fund-projects&catid=106:health-research-projects&Itemid=98) that they have identified regions on two chromosomes in the 3 breeds that they believe contain one, or more, genetic risk factors. Research ongoing at present will seek to identify the precise genetic alterations within the two chromosomal regions that are associated with an increased risk of developing TCC of the bladder. This research will form the basis of a DNA test to identify US Scottish Terriers that have an increased risk of developing TCC of the bladder.

If the majority of Scottish Terriers in the US are relatively recent descendants of UK lines, and ‘transatlantic breeding’ between the UK and US populations is ongoing, it is likely that UK dogs will share the same genetic risk factors for bladder TCC as US Scottish Terriers. However, the only way to prove this is to collect DNA samples (cheek swabs) from small numbers of both affected and ‘elderly’ unaffected UK dogs (e.g. 5-10 of each group) and ask the US researchers if they would evaluate if the UK dogs share the same genetic risk factors as the US dogs. If the US researchers were unable to cover the cost (£1000-£2000) of analysing the DNA samples from the UK dogs, the money would have to be found elsewhere. If the UK dogs are found to possess the same genetic risk factors as the US dogs any DNA test arising from the research conducted in the United States could be used to identify UK Scottish Terriers that have an increased risk of developing bladder TCC. Conversely, if it appears that the UK dogs are likely to contain different genetic risk factors to those possessed by the US dogs then there is the motivation for a research study to identify genetic risk factors for bladder TCC in UK Scottish Terriers.

The Animal Health Trust (http://www.aht.org.uk/) has agreed to assist the Scottish Terrier Breed Council and UK Scottish Terrier Clubs to collect cheek swabs from Scottish Terriers (of any age) affected by bladder TCC, and Scottish Terriers that are at least 7 years old and have never had any form of cancer. For the genetic analyses to be possible the dogs must be purebred. Cheek swabs kits can be obtained from the Animal Health Trust (Tel.: 01638 751000 ext. 1214; E-mail: oncologyres@aht.org.uk). As the Trust has little prospect of securing grant funding (for a research study on bladder TCC) that would reimburse the cost of sample collection, a donation of £5.00 is requested for each cheek swab kit.”

 


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