Johannesburg - A lump found on an ancient jaw bone suggests that tumours and humans have had a long relationship that stretches back way before the ills of modern living.
Scientists believe they have found evidence of a small benign tumour on the right lower jaw of a Homo naledi specimen.
This announcement comes as the Almost Human exhibition opened at Maropeng, billed as the largest public display of ancient fossil hominins, this week.
On display are Homo naledi skeletons from the Dinaledi and the newly discovered Lesedi chamber in the Rising Star cave system.
Edward Odes of Wits University, the lead researcher in the study, says it’s not known what the effect this non-life threatening tumour would have had on the adult naledi.
“It could have swelled up and caused a bit of discomfort,” he says.
He and his fellow researchers found the tumour using Micro CT scans and have published their findings in the latest copy of the International Journal of Paleopathology
The presence of the tumour may have made it difficult to chew. This is not the first tumour or cancer to have been discovered in the human fossil record.
Odes found evidence of osteosarcoma, an aggressive form of bone cancer, on a 1.7 million-year-old foot bone.
The foot bone was found at Swartkrans in the Cradle of Humankind. It’s not known if the cancer killed the individual.
Evidence for the earliest known bony tumour in human prehistory was found not far from the Swartkrans site at Malapa also in the Cradle of Humankind.
This tumour was discovered on the 1.98 million-year-old vertebra of an Australopithecus sediba child.
The tumour, believes Odes, probably made it difficult for the sediba to climb.
The latest tumour discovery is likely to help in our understanding of both tumours and cancers.
“What this means is that cancers and tumours are not a recent phenomenon,” says Dr Patrick Randolph-Quinney, of the University of Central Lancashire in the UK.
“We tend to think of cancer in particular as being a recent condition. An estimated eight million people around the world die from cancer each year, making the disease one of the most common causes of death in modern humans, yet the origins of cancer have remained a mystery for many years.”
Randolph-Quinney added that many arguments around the causes of the disease blame modern lifestyles and environments.
“While it’s true that the number of people affected by different types of cancer has risen since the industrial revolution, groundbreaking research in 2016 found that the origins of cancer in the human family go back much further than we anticipated, in fact to almost two million years as we discovered last year with fossils from Swartkrans and Malapa caves,” Randolph-Quinney adds.
It was just over two weeks ago that scientists announced the date for the Homo naledi skeletons that were discovered in the Dinaledi chamber.
Through using various dating techniques, an international team of scientists were able to date the skeletons to between 236 000 and 335 000 years.
But what still baffles scientists is how the naledi individuals ended up in the cave system.
It’s been suggested that Homo naledi was placing its dead in the cave.
Odes says that there is no signs of trauma on the skeletons, and believes this would be unusual if this was some type of prehistoric cemetery.
“The remains were remarkably healthy; the question is what killed them off?”
Those well-preserved mysterious remains in the Rising Cave system could one day provide more insight into the long relationship we have had with cancer.
Some of these cancers, explains Odes, are caused by viruses, and traces of their existence might still lie with those skeletons.
“Inevitably, DNA is the next frontier that we are going to have to shoot for. That will identify viral signatures and disease markers,” says Odes.