Squamous Cell Carcinoma (SCC)
Squamous cell carcinoma (SCC) is the most common cancer affecting the equine eye. At an increased risk of developing this disease are Appaloosas, paints, pintos, Haﬂingers, (Belgians, Shires, and Clydesdales) and any horse lacing pigment in or around the eye.
Research has shown that a recessive DDB2 missense variant C>T can be used as a risk factor for developing SCC. Roughly 88% of the cases studied were homozygous for the variant.
Testing for SCC is valid for Haflinger and Belgian breeds, and may also be tested in Percherons. Current list will be updated when additional breeds are validated.
|R/R||At Risk||The horse carries two copies of the variant and is homozygous for the mutation. The horse has a higher likelihood of developing limbal squamous cell carcinoma (SCC).|
|n/R||Carrier||Both the normal and mutant alleles were detected. Horse tested heterozygous and is a carrier of the gene mutation.|
|n/n||Clear||Horse tested negative for the variant and does not carry the gene mutation. The horse will not pass on the defective gene to its offspring.|
Bellone RR, Liu J, Petersen JL, Mack M, Singer-Berk M, Drögemüller C, Malvick J, Wallner B, Brem G, Penedo MC, & Lassaline M. (2017) A Missense Mutation in Damage-specific DNA Binding Protein 2 Is a Genetic Risk Factor for Limbal Squamous Cell Carcinoma in Horses. Int. J. Cancer 141(2):342-353.
Lassaline M, Cranford TL, Latimer, CA, & Bellone R. (2015) Limbal squamous cell carcinoma in Haflinger horses. Vet Ophthalmol 18(5) 404-408.
Submit a Sample for Testing:
To submit a sample for testing please click on ORDER and download a sample submission form. Then follow the sample collection and submission instructions.