Cancers and tumours plagued human ancestors for millions of years, challenging the assumption that they are caused by modern lifestyles, new research has shown.
The discovery of a foot bone approximately 1.7 million years old, with definitive evidence of malignant cancer, pushed the oldest date for this disease back from recent times into deep prehistory, the University of the Witwatersrand said in a statement on Thursday.
The bone was found in the Swartkrans cave, in the Cradle of Humankind. The exact species to which the foot bone belonged was still unknown, but it was clearly a hominin, or bipedal human relative.
In addition, the oldest tumour ever found in a human fossil was around two million years old, beating the previous record of 120 000 years. And it was found in a child.
It was a benign neoplasm found in the vertebrae of the well-known Australopithecus sediba child, Karabo, at the Malapa site, also in the Cradle of Humankind. The oldest previously demonstrated possible hominin tumour was found in the rib of a Neanderthal and dated to around 120 000 years old.
“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 doctoral candidate.
The findings were published in the South African Journal of Science’s July/August issue. The research was conducted by a team of international scientists, led by Wits’s Evolutionary Studies Institute and the South African Centre for Excellence in Palaeo Sciences.
Karabo’s tumour was fascinating because it was in the back, an “extremely rare” place for it to be found in modern humans, but also because it developed in a child, said one of the researchers, Dr Patrick Randolph-Quinney of Wits and the University of Central Lancashire in the UK.
“This in fact is the first evidence of such a disease in a young individual in the whole of the fossil human record”.
Professor Lee Berger said the evidence of a tumour in a child questioned the assumption that modern humans developed them as a consequence of living longer.
Both incidences of disease were diagnosed using state-of-the-art imaging technologies at the European Synchrotron Research Facility in Grenoble, France, medical CT at the Charlotte Maxeke Hospital in Johannesburg, and the micro-CT facility at the Nuclear Energy Corporation of SA in Pelindaba.