Researchers have found the earliest evidence of bone cancer in the rib of a 120,000-year-old Neanderthal from Krapina, Croatia.
A team of researchers studied the Neanderthal bone, which is a 30-millimetre-long fragment of the left rib that shows a fresh break. The break in the rib exposes a chamber that is 18 millimetres in length and 7.6 millimetres wide. Based on radiograph and CT scans, researchers found that rib is afflicted wihth benign tumor associated with fibrous dysplasia that is still seen in modern humans today. Fibrous dysplasia is a chronic condition of the skeleton where an abnormal type of fibrous bone is formed by the cells, as a result of gene mutation.
"It wasn't a small tumor," co-author of the study David Frayer, professor of anthropology at the University of Kansas, US, said in a statement. "It was a fairly large one, probably bulging at the base of the rib. We're not sure how far along it was, but it was well-expressed in the bone. It was in the upper third of the back, and muscles attach there that are associated with raising the arm."
According to the researchers, it is very difficult to find evidence of cancer in pre-historic ancestors as they lived a short life in pristine environment. Cancer in modern humans is caused by exposure to toxins, radiation and pollution.
The research team was surprised when they found evidence of cancer in a Neanderthal bone. The bone was unearthed before 1905 in a cave in Croatia. The site had more than 900 Neanderthal bones that dated back 120,000 to 130,000 years ago. Except for one Neanderthal bone, the rest did not show evidence of tumor.
The tumor bone is 100,000 years older than the previous tumor found in an Egyptian mummy. Frayer said that the newly-found tumor bone is the earliest evidence of cancer in the human fossil record.
He also said that the tumor bone is not associated with the complete skeleton of the Neanderthal. So researchers are not aware if the tumor is inflicted in a male or a female. They were not able to determine the age of the adult individual at the time of the death or even the cause of the death.
The details of the findings are published in the journal PLOS ONE.