By TAKURO YAMANO/ Staff Writer
July 22, 2020 at 07:00 JST
A Jack Russell terrier (Asahi Shimbun file photo)
GIFU--Researchers who stumbled on a previously unknown hereditary disease in a breed of dog said the discovery could prove to be a breakthrough in ascertaining how cancer develops in both canines and humans.
The disorder characterized by gastrointestinal polyps was identified by a team of researchers headed by Akihiro Hirata, an assistant professor of veterinary pathology at Gifu University, and Hiroki Sakai, a veterinary pathology professor at the college.
Comparing the symptoms of hereditary gastrointestinal polyposis with a congenital condition in humans is expected to offer new insights into the tumor formation processes.
"Dogs often develop tumors in their stomachs," Hirata noted. "If we manage to spot the factor that promotes their gastric tumor formation, the carcinoma development mechanisms in humans may become clearer."
Hereditary gastrointestinal polyposis only occurs in the Jack Russell Terrier breed. Different symptoms arise, depending on where polyps emerge. For example, gastric and colorectal ones lead to vomiting and bloody feces, respectively.
Dogs with the disease recover more smoothly than their counterparts with ordinary gastrointestinal tumors. The disorder is rarely fatal.
However, therapeutic methods have eluded researchers so far, so polyps are usually removed through surgery.
A pet boom in Japan has highlighted a rapidly growing number of cases of dogs and cats with hereditary conditions. The university team started its survey in 2015 after discovering that Jack Russell terriers were increasingly being diagnosed as having gastrointestinal polyps at the Animal Medical Center of Gifu University.
There are two kinds of polyps: neoplastic ones and non-neoplastic polyps, including inflammatory polyps. An examination of 21 Jack Russell terriers showed they all had neoplastic polyps.
An analysis also found that most of the dogs developed multiple polyps, especially among younger animals. These traits cannot be detected in canines with ordinary gastrointestinal tumors.
The disorder has much in common with familial adenomatous polyposis among humans, so the researchers studied the adenomatous polyposis coli (APC) gene, which causes the disease.
The results showed the same congenital genetic mutation in canines as in human patients, meaning that the condition is a previously unknown one, according to the team.
If a genetic test is developed based on the find, it will allow veterinarians to make a confirmed diagnosis using the technique and take precautions against a possible recurrence. The earlier the disease is detected, the more likely that appropriate treatment can be offered.
By including the new disease in a genetic test used by dog breeders for their breeding business, the researchers said it will prevent the gene mutation from being passed through the generations, eventually leading to eradication of the condition.
The findings were released in the online edition of the international cancer research journal Carcinogenesis published in Britain.
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