Scientists for the first time have identified an aggressive bone cancer in a dinosaur that lived nearly 77 million years ago.
The cancerous lower leg bone (fibula) is from a horned dinosaur called a Centrosaurus apertus. At first, researchers thought the bone had been broken and was healing when the animal died, but state-of-the-art technology showed it had a cancer known as an osteosarcoma.
“Diagnosis of aggressive cancer like this in dinosaurs has been elusive and requires medical expertise and multiple levels of analysis to properly identify,” said Mark Crowther, a professor of pathology and molecular medicine at McMaster University in Canada.
“Here, we show the unmistakable signature of advanced bone cancer in [a] 76-million-year-old horned dinosaur — the first of its kind. It’s very exciting,” he said in a news release from the Royal Ontario Museum.
To make the diagnosis, Crowther and his team used high-resolution CT scans and three-dimensional CT reconstruction, which showed the progression of cancer through the bone.
To be certain, they compared the fossil with a normal fibula from a dinosaur of the same species and with a human fibula with osteosarcoma.
Although cancer might have killed the dinosaur in time, the fossil was found in a bonebed, suggesting that it died with a large herd of Centrosaurus in a flood.
“The shin bone shows aggressive cancer at an advanced stage. The cancer would have had crippling effects on the individual and made it very vulnerable to the formidable tyrannosaur predators of the time,” said researcher David Evans, an expert in vertebrate paleontology from the Royal Ontario Museum.
“The fact that this plant-eating dinosaur lived in a large, protective herd may have allowed it to survive longer than it normally would have with such a devastating disease,” Evans noted.
The researchers said it was inspiring to see a multidisciplinary effort similar to that used in diagnosing and treating osteosarcoma in human patients leading to the first diagnosis of osteosarcoma in a dinosaur.
Links between human disease and the disease of the past can help scientists gain a better understanding of the evolution and genetics of disease, the researchers said.
The report was published Aug. 3 in the journal The Lancet Oncology.
For more on bone cancer, head to the American Cancer Society.