Some English bulldogs diagnosed with a common cancer may instead have a newly described, non-cancerous syndrome called polyclonal B‐cell lymphocytosis, according to a press release.

The discovery was made by Morris Animal Foundation-funded researchers at Colorado State University during a study to better understand B-cell chronic lymphocytic leukemia (BCLL). The team published their findings in the Journal of Veterinary Internal Medicine.

The dogs may look to their veterinarians like they have leukemia, but they don’t actually have cancer, according to the research and press. Rather than being at high risk for BCLL as originally thought, English bulldogs develop a benign syndrome that has many similarities to leukemia. The syndrome almost certainly has an underlying genetic cause and does not appear to have a malignant clinical course.

“This could save some dogs from being misdiagnosed, treated for cancer or even euthanized when they shouldn’t be,” said Dr. Anne Avery, Professor, Department of Microbiology, Immunology and Pathology at Colorado State University, in the press release.

The new research stems from a previous paper published by Dr. Avery’s team. In that paper, researchers identified different breeds at an increased risk for that tumor type. English bulldogs were among the breeds, but compared to the other breeds, English bulldogs were significantly younger when they presented with symptoms and also had other differences that led researchers to wonder whether English bulldogs truly had BCLL or a different, previously unidentified disease.

For the new study, the team identified 84 cases with increased numbers of B-cells in the blood, drawn from their database of 195 English bulldogs. The team analyzed the serum of these dogs to determine the types of antibodies they produced. Since many of the dogs had enlarged spleens, the team also took a closer look to see what kinds of cells expanded there.

The team found that 70% of the dogs did not have cancer. These dogs tended to be young, some just 1 or 2 years old when they developed the syndrome. Three-quarters of the dogs were male, and more than half had enlarged spleens. Most of the cases had hyperglobulinemia, an excess of antibodies in the blood stream. The team hypothesized that this syndrome has a genetic basis.

The team is looking for evidence of this syndrome in other breeds, but they believe it is rare in dogs other than English bulldogs.

The group’s next step is to look for the genetic mutation that leads to this syndrome. They would also like to follow the dogs for a longer period to learn if there are health consequences to persistently high B-cell numbers.

Morris Animal Foundation, headquartered in Denver, is one of the largest nonprofit animal health research organizations in the world, funding more than $136 million in studies across a broad range of species. Learn more at morrisanimalfoundation.org.