Dinosaurs can develop cancer – Osteosarcoma diagnosed in leg fossil remain

A recent study published at Lancet Oncology discovered osteosarcoma, a malignant bone cancer in a dinosaur fossil record [1].

Osteosarcoma is a malignant bone cancer, with an annual incidence of 5 cases per million persons per year [2]. It is also the earliest human cancer ever known: the first case of osteosarcoma was discovered in a foot bone of an early human ancestor, from the Swartkrans Cave, South Africa [3]. In human, osteosarcoma is often seen in young adults and adolescents. Abnormal bone-forming cells gain uncontrollable growth, forming abnormal bone, which is weak, prone to fracture and destroys normal bone. Patients often feel pain, a palpable lump or unexplained limp [4].


© Bone Cancer Research Trust, UK. 

The fossil specimen diagnosed of osteosarcoma was collected in South Alberta, Canada in 1989. It belonged to a herbivorous, middle-size dinosaur (Centrosaurus apertus) with firm limbs [1]. This dinosaur was around the North America continent about 76 million years ago, during the Cretaceous era. It had a deformed fibula—a bone from the lower leg. Paleontologists initially thought it was due to a fracture that hadn’t healed cleanly [5].

In 2017, a research team led by David C. Evans, a dinosaur expert at Royal Ontario Museum and prof. Mark A. Crowther from department of medicine at McMaster university, analyzed the deformed fibula. After gross morphology, radiological examination (e.g. X-ray, CT and MRI) and histological examination, the fibula was compared to a confirmed case of human osteosarcoma and a normal Centrosaurus fibula. They finally identified that abnormal structure to be an advanced apple-sized osteosarcoma [1,5].


© Royal Ontario Museum/McMaster University

Researchers first assumed this dinosaur died of advanced osteosarcoma, or being captured by a carnivorous predator because of the limp. However, the fossil was found in a bone bed with lots of other Centrosaurus specimens, so that it likely died of a massive disaster together with the rest of its herd, like a flood [5].

This is not the first case of cancer found in fossil remains. Scientists have identified (i) a benign tumor in Tyrannosaurus rex fossils, (ii) osteoblastoma and desmoplastic fibroma in duck-billed hadrosaurs, and (iii) a periosteal osteosarcoma in a 240-million-year-old turtle fossil [6-8]. But according to Evans and Crowther, their study was the first to confirm a dinosaur cancer diagnosis at the cellular level, and their diagnosis showed a more careful look at unusual fossil malformations using modern imaging and diagnostic techniques, leading to new insights about the evolutionary origins of diseases [5].



[1] Ekhtiari, S., Chiba, K., Popovic, S., Crowther, R., Wohl, G., Wong, A. K., . . . Evans, D. C. (2020). First case of osteosarcoma in a dinosaur: A multimodal diagnosis. The Lancet Oncology, 21(8), 1021-1022. doi:10.1016/s1470-2045(20)30171-610.1016/S1470-2045(20)30171-6

[2] Broadhead, M. L., Clark, J. C., Myers, D. E., Dass, C. R., & Choong, P. F. (2011). The Molecular Pathogenesis of Osteosarcoma: A Review. Sarcoma, 2011, 1-12. doi:10.1155/2011/959248

[3] Odes, E. J., Randolph-Quinney, P. S., Steyn, M., Throckmorton, Z., Smilg, J. S., Zipfel, B., . . . Berger, L. R. (2016). Earliest hominin cancer: 1.7-million-year-old osteosarcoma from Swartkrans Cave, South Africa. South African Journal of Science, Volume 112(Number 7/8). doi:10.17159/sajs.2016/20150471

[4] https://www.bcrt.org.uk/news/2016/08/osteosarcoma-the-worlds-oldest-known-cancer

[5] https://www.sciencemag.org/news/2020/08/doctors-diagnose-advanced-cancer-dinosaur

[6] Rothschild, B. M., Tanke, D. H., Helbling, M., & Martin, L. D. (2003). Epidemiologic study of tumors in dinosaurs. Naturwissenschaften, 90(11), 495-500. doi:10.1007/s00114-003-0473-9


[8] https://www.history.com/news/oldest-cancer-triassic-fossil