Dogs provide information about brain tumor development in humans

Gliomas are very severe human brain tumours that are rarely curable. Glioma can also occur in dogs and some brachycephalic dog breeds, such as Boxer and Bulldog, have a considerable elevated risk of this type of brain tumour.

'In our study we hypothesized that since the brachycephalic dog breeds with elevated risk are closely related we would be able to identify a genomic region shared by those breeds. The same risk factors for glioma could also be present in other breeds and the way to identify the genomic region would be to compare genetic markers from dogs diagnosed with glioma from several breeds to healthy controls. Based on this we then performed several genetic analyses to narrow down the region in the genome', says Katarina Truvé, first author of the paper and former doctoral student at the Swedish University of Agricultural Sciences.

The genetic analyses were performed using 25 different dog breeds and the researchers could identify an area in the genome that differed between diseased and healthy dogs. This region also showed signs of selection in the brachycephalic dog breeds at high risk of developing glioma. This means that genes that are important for glioma development could be located in the same genomic region as genes that have been promoted in the breeding for specific traits in these brachycephalic dog breeds. In this area of the genome the researchers then identified three genes as the most associated with the development of glioma in dogs.

Humans have the same genes as the ones identified by the researchers in dogs. They therefore went on to determine whether there was also a link between the identified genes and human glioma.

'We compared for instance how active the genes were in tumour tissues and normal brain tissue. We found that especially one of the genes showed reduced activity in tumour tissue. These results indicate that further investigations of the role of these three genes in glioma development would be of interest, with potential benefit to both dog and human', says Karin Forsberg Nilsson, professor at the Department of Immunology, Genetics and Pathology and Science for Life Laboratory, who has been responsible for the analyses of human brain tissues in the study.

The study is a collaboration between researchers at Uppsala University, Swedish University of Agricultural Sciences and University of Califonia, Davis, USA. The results have been published online in the journal PLOS Genetics.