Malignant cancer diagnosed in a dinosaur for the first time

Centrosaurus apertus

Osteosarcoma is, in humans, the most common primary malignant bone tumor. And for the first time, researchers at the Royal Ontario Museum and McMaster University (Canada) have diagnosed this type of bone cancer in a dinosaur. A Centrosaurus apertus, a large herbivore that lived about 77 million years ago.

The dinosaur’s fibula – a leg bone – affected by the dinosaur was discovered in Alberta, Canada, in 1989. Its deformed end was first analyzed as presenting a healing fracture. But then unusual properties were observed and the researchers wanted to know more.


High-resolution computed tomography, examination of thin sections under a microscope, 3D reconstruction by computed tomography then comparison with a healthy dinosaur fibula and a fibula from a human with osteosarcoma; nothing has been left to chance by the multidisciplinary team. Conclusion: “For the first time, we show the indisputable signature – at the molecular level – of advanced bone cancer in a dinosaur,” said Mark Crowther, paleontologist, in a statement from the Royal Ontario Museum.

The researchers even claim that the cancer was at an advanced stage and could have invaded other systems. Probably even hurt the dinosaur. But the Centrosaurus apertus fibula was found among those in what appears to be a large herd struck by flooding. “The fact that this dinosaur lived in a large protective herd may have allowed it to survive longer than it would normally have with such a severe disease,” notes David Evans, researcher, in conclusion.

Researchers are now waiting to apply this method to other fossils. Because the in-depth study of these diseases that we share with dinosaurs could help them better understand and fight them.

This pathology would thus have remained globally unchanged for a very long time, regardless of the creature affected. Researchers have analyzed 10,000 dinosaur vertebrae from more than 700 museum specimens in North America using a portable x-ray machine.

Only one group would have suffered from a tumor: hadrosaurs or duck-billed dinosaurs. The team found 29 tumors in the bones from 97 individuals of this group of herbivores from the Cretaceous period. The most common tumors were hemangiomas, benign tumors of the blood vessels, present in 10% of humans. The edmontosaurus, which measured 3.5 meters, was the only species in which a malignant tumor was found.

The question of cancer in dinosaurs has already been discussed but this time it is the first large-scale investigation into this matter. What made hadrosaurs sick? The question has not yet been decided by scientists. Bruce Rothschild of the Northeastern Ohio Universities College of Medicine (Rootstown, USA), who participated in the study, says they ate conifers, which are high in chemical carcinogens. Little is known about diseases in dinosaurs, says paleontologist David Norman of the University of Cambridge (United Kingdom).

Cancers are common in the living world, but their frequency is still unknown for most species.

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