Osteosarcoma update

Printed in November /December 2008 and reproduced with the kind permission of the Claymore and the author John Dillinger D.V.M.

This year the SDCA continued its collaboration with Dr Marlene Hauck at North Carolina University to study osteosarcoma. This effort is described in more detail below.

In 2004 the SDCA Board approved funding of an $18,246 grant to support this research, using money from the Canine Health Foundation ( CHF ) Donor -- Advised “ Bunnie Austin” Fund. The first instalment of $9,123 was paid in March 2006. The second instalment of $9,123 was paid in March 2007.

During the past year, Dr Hauck entered into collaboration with Dr Elaine Ostrander at the National Institutes of Health to try a different approach to screening Deerhounds DNA samples for regions related to osteosarcoma risk. The new approach uses a canine genome map defined by markers that are short nucleotide polymorphisms (SNPs) instead of microsatellites.

The rationale for this decision was that the gaps between markers are smaller in the SNP map than in the microsatellite map; however, the gaps are still large, so that each SNP marker identifies a region that contains many genes.

The initial screen using SNP map identified two markers associated with increased osteosarcoma risk---- one that is strongly associated with risk and another that is more weakly associated. This is fantastic news for us!

Drs. Hauck and Ostrander have reviewed known genes in the region of the SNP that is strongly associated with osteo risk, and they have identified one “candidate” gene. ( A candidate gene is one suspected to play a role in cancer because it is related to cell division, cell migration, etc ) Dr Hauck is presently sequencing sections of this gene in Deerhound DNA samples to see if there is indeed a specific difference between Deerhounds that develop osteosarcoma and those that do not. Unfortunately, the DNA sequencing process is a slow one, so it may be many months before we have an answer.

If Dr Hauck finds a form of the candidate gene that is associated with increased osteosarcoma risk, then we will have a home run. If she doesn’t, then we and she are looking at a lot more work----basically, sequencing the entire DNA in the region of the SNP marker that is strongly associated with osteo risk, from dozens of Deerhounds, to look for a difference between dogs that get cancer and those that don’t. This is a region of approximately 20 million base pairs.

So, the good news is that we have discovered at least one--- and maybe two--- regions of DNA associated with osteosarcoma risk in Deerhounds. This is a big first step toward eventually finding an osteosarcoma gene and developing an osteosarcoma genetic screening test.

John Dillinger D.V.M.