The first words that come to mind when people hear “Triassic” are likely dinosaur or maybe ginkgo or possibly even phytoplankton, but probably not cancer. For all that we have learned about how cancer develops based on the efforts of numerous research scientists, this disease is not solely a modern affliction. In fact, cancer has deep roots in the past. From several thousand year old human mummies to fossils millions of years old, cancer has left evidence of its presence in the historical record. Yes, even in the era of dinosaurs, cancer existed.
Cancer is usually a soft-tissue-based malady, but occasionally, it can also be found on bones, altering the bone’s surface and leaving unmistakable signs. Alterations like those observed on the femur of a 240-million-year-old shell-less stem-turtle found in modern-day Germany and described in JAMA Oncology.
Researchers examined the surface of the reptilian left femur with a stereo microscope and generated interior images using virtual sections from a micro computerized tomography (CT) scan. The micro CT X-ray scans were combined into a 3D reconstruction of the bone. Even a visual inspection could spot the roughened, pocked areas of the fossil’s left femur, indicating something had happened to the bone.
The diagnosis 240 million years after the stem-turtle died and became fossilized: Periosteal osteosarcoma. This conclusion was based on several characteristics seen in the radiography, including the large, broad attachment to the cortical bone (meaning not a bone spur), the sharp, spiny outgrowths on the mass, no involvement with structures deeper in the bone and the wrinkled texture of the area affected. As it turns out, the surface bone tumor was noted by Haridy et al. as one of the oldest known examples of cancer found in an aminiote, vertebrate animals that include birds, reptiles, dinosaurs and mammals.
The Triassic stem-turtle in which this bone cancer was found is called Pappochelys rosinae. Pappochelys means grandfather turtle in reference to the fossil as a recently discovered link between turtles and the main group of reptiles such as lizards and snakes. In this case, grandfather could also refer to the osteosarcoma found on the fossil skeleton, demonstrating that cancer is far from a recent phenomenon and has been present in vertebrates for millions of years.
Haridy, Y., Witzmann, F., Asbach, P., Schoch, R.R., Fröbisch, N. and Rothschild, B.M. (2019) Triassic cancer–Osteosarcoma in a 240-million-year-old stem-turtle. JAMA Oncol. doi: 10.1001/jamaoncol.2018.6766