A bone from a hominin ancestor who lived some 1.8 million to 1.6 million years ago shows signs of cancer, NPR reports. This, it adds, is the oldest known instance of the disease within a hominin ancestor.
Researchers from University of the Witwatersrand report in the South African Journal of Science that advances in three-dimensional imaging enabled them to uncover a malignant osteosarcoma in a foot bone that was first uncovered in Swartkrans cave — part of Cradle of Humankind World Heritage site — between 1960 and 1980. They write that the mass has "an irregular spongy woven bone texture with a cauliflower-like external appearance."
NPR notes that a doctoral student had noticed the tumor earlier, but thought it was a benign osteoid osteoma. With a new high-resolution X-ray technique, though, the Wits researchers have now come to a different conclusion.
"[W]hilst the upsurge in malignancy incidence is correlated with modern lifestyles, there is no reason to suspect that primary bone tumors would have been any less frequent in ancient specimens," the Wits researchers write. "Such tumors are not related to lifestyle and often occur in younger individuals. As such, malignancy has a considerable antiquity in the fossil record, as evidenced by this specimen. "
NPR adds that while this is the oldest instance of a malignant tumor in a human ancestor, tumors have also been found in the bones of dinosaurs.