“Diagnosis of aggressive cancer like this in dinosaurs has been elusive and requires medical expertise and multiple levels of analysis to properly identify,” Crowther said in a press release by the ROM. “Here, we show the unmistakable signature of advanced bone cancer in 76-million-year-old horned dinosaur — the first of its kind. It’s very exciting.”

Evans said the lower leg bone contained “a massive gnarly tumor larger than an apple.”

The researchers — assembled from a variety of different fields — diagnosed the tumor using high-resolution CT scans, where they observed thin sections under the microscope to assess it at a cellular level.

Most tumors occur in soft tissue that doesn’t willingly fossilize, so there is little evidence of cancer in fossil records, according to Reuters.

The study’s findings could establish links between ancient and modern animals and even help scientists learn more about the evolution and genetics of various diseases.

Illustration of two Centrosauruses (Photo by De Agostini via Getty Images/De Agostini via Getty Images)

Illustration of two Centrosauruses (Photo by De Agostini via Getty Images/De Agostini via Getty Images)

“Evidence of many other diseases that we share with dinosaurs and other extinct animals may yet be sitting in museum collections in need of re-examination using modern analytical techniques,” the release said.

Tumors were also found in a dinosaur earlier this year, although a malignant cancer diagnosis has yet to be confirmed.

“This finding speaks to the biology of cancer. It is not something novel or new, but probably has occurred since time immemorial and is an expected complication in all animals,” added Crowther, according to the news organization.

While the Centrosaurus was likely weak from cancer before it died, Evans said the disease may not have killed the dinosaur. The fossil was found in a bonebed containing the remains of hundreds of other Centrosaurus dinosaurs, which suggested that they died in a flood.

“This remarkable find shows that no matter how big or powerful some dinosaurs may seem, they were affected by many of the same diseases we see in humans and other animals today, including cancer,” he added, according to Reuters. “Dinosaurs seem like mythical beasts, but they were living, breathing animals that suffered through horrible injuries and diseases.”