Two recent recent discoveries, of a 1.7 million-year-old cancerous foot bone and a two million-year-old vertebrae ravaged by tumours, show that cancer has been bothering us for a while. So it's not strictly a modern disease. A cancerous foot bone belonging to a 1.7 million year old hominid. (Image: Edward J. Odes et al., 2016)
Researchers from the University of the Witwatersrand (Wits) in Johannesburg discovered the 1.7 million-year-old cancerous foot in South Africa's Swartkrans Cave, a site renowned for its rich archaeological treasures, especially ancestral human remains. The exact species to which the bone belonged to is still unknown, but it likely came from a hominid, or bipedal human relative. In a paper published in the South African Journal of Science, the researchers say it's the oldest definitive evidence of malignant cancer in a proto-human.
A cut-away of the bone. The spongy tumour is designated as (v). (Image: Edward J. Odes et al., 2016)
The cancer was identified as an osteosarcoma, an aggressive cancer that typically afflicts younger modern humans. If left untreated, it can result in early death.
"Due to its preservation we don't know whether the single cancerous foot bone belongs to an adult or child, nor whether the cancer caused the death of this individual," Bernhard Zipfel, a Wits scientist and co-author of the study, said in a statement. He said the cancer would have affected this individual's ability to walk or run, making those activities quite painful.
In a related paper published in the same journal, a collaborating team of scientists describe the oldest tumour ever found in the human fossil record -- a benign tumour found in the vertebrae of an Australopithecus sediba child, a well-studied bipedal species. The bony tumours were uncovered in Malapa, also in South Africa, and are almost two million years old. Prior to this discovery, the oldest known hominin tumour was found in the rib of a Neanderthal dating back to around 120,000 years ago.
tumours found on the vertebra of an Australopithecus sediba specimen are shown in pink. (Image: P. S. Randolph-Quinney et al., 2016)
"The presence of a benign tumour in Australopithecus sediba is fascinating not only because it is found in the back, an extremely rare place for such a disease to manifest in modern humans, but also because it is found in a child," lead author Patrick Randolph-Quinney from the University of Central Lancashire said in a statement. "This in fact is the first evidence of such a disease in a young individual in the whole of the fossil human record."
These discoveries challenge the modern assumption that cancers and tumours are caused by modern lifestyles and environments. "[Our] studies show the origins of these diseases occurred in our ancient relatives millions of years before modern industrial societies existed," said Edward Odes, a Wits scientist who contributed to both papers. The nature of cancer and its origins are clearly more complex that we thought.