There’s still no cure for Squamous cell carcinoma (SCC) in horses, but a new study from UC Davis can help detect horses at risk for it.
SCC is one of the most common cancers that hits equines in their eyes, and the second most common tumor in horses, according to UC Davis. The cause is a genetic mutation that is believed impacts the damage-specific DNA-binding protein 2 (DDB2) gene’s ability to seek and repair UV damage. Scientists from the university announced their findings in the International Journal of Cancer.
“The mutation is predicted to alter the shape of the protein so it can’t recognize UV-damaged DNA,” said Dr. Rebecca Bellone, an equine geneticist at the Veterinary Genetics Laboratory and associate adjunct professor at UC Davis School of Veterinary Medicine. “We believe this is a risk factor because cells can’t repair the damage and accumulate mutations in the DNA that lead to cancer.”
The effects of ocular SCC can be devastating: It can lead to vision loss and even loss of the eye. In more advanced cases, SCC can be locally invasive and spread to the orbit and eat away at bone and eventually the brain of a horses—leading to loss of life. These recent study results offer a huge application in identifying horses at risk for developing SCC on two fronts, allowing breeders to make informed decisions.
“One, it’s important for the individual horse with a known risk and we can be more vigilant about exams as well as protecting their eyes from UV exposure,” Lassaline said. “If detected early, we can remove the tumor and save the eye. Secondly, that knowledge is important for making informed breeding decisions.”
This research was supported in part by donations from the Center for Equine Health as well as the Morris Animal Foundation.