Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Friday, September 16, 2016

Everything New Is Old Again

"The expression of malignant osteosarcoma indicates that whilst the upsurge in malignancy incidence is correlated with modern lifestyles, there is no reason to suspect that primary bone tumours would have been any less frequent in ancient specimens."
Research paper, South African Journal of Science

"[Cancer that] a striking rarity of malignancies [in the anthropological record suggests that cancer is] limited to societies that are affected by modern lifestyle issues such as tobacco use and pollution."
Egyptologists writing in the journal Nature Reviews

"We don't have anything to report on pathology from these fossils yet [Homo naledi fossils, discovered in 2013]."
"Some really interesting aspects of health leave only very subtle traces on bone [in primitive fossils], so we can't definitively rule anything out."
John Hawks, paleontologist, Johannesburg

The oldest known case of cancer having occurred in an early human ancestor called a protohuman who lived 1.7 million years ago in the Early Pleistocene era was unearthed by a team in the countryside of South Africa. There seems little practical reason not to believe that the same natural threats to human health caused by exposure to the ultraviolet radiation from the sun and radon seeping out of the ground, did not pose a health hazard to early versions of humankind, and on through the ages.

Viruses, similar to those in our present environment, also causing a threat to human health, circulated in primitive eras and had the same effect of corrupting DNA to produce cancer. Hormones known to become active during certain periods of life, accelerating cell multiplication, increasing mutations likelihood represent an internal threat to longevity, with the onset of cancer; then and now. Science points at external sources that invade organisms, causing cancer, but causes are complex and various.

Evidence of a cancerous tumor was found on a bone fossil dating back 1.7 million years. Credit Patrick Randolph-Quinney/University of Central Lancashire
Paleoanthropologists discovered ancient fossilized remains in Swartkrans Cave, located northwest of Johannesburg, producing a research paper describing the discovery of an osteosarcoma in fossilized protohuman remains, describing the find as the most ancient known instance of cancer discovered in a human ancestor.

There is a tendency to believe on the basis of knowledge of cancer prevalence that in modern times humans are more susceptible to cancers than at any other time in human history. Overlooking the fact that human life-expectancy is far greater now than at any other time in human history, and most cancer is acknowledged as a disease of old age, for the most part. Osteosarcoma, of the type discovered in the ancient fossil happens in younger people, responding to spurts of growth in limbs.
In 1932, anthropologist Louis Leakey, top, and his crew discovered a fossilized jawbone in Kenya with an abnormal-looking growth. At the time, Leakey claimed it was the oldest evidence of early human ancestors. While that view has changed, the fossil is still considered remarkable for the possible tumor it carries on its left side. Now housed at the Natural History Museum in London, the bone is known as the Kanam mandible, named after the fossil bed where it was found.
John Reader/Science Source

Kanam Man, who lived some 700,000 years ago in East Africa was held, when it was discovered in 1932,  to be the previous oldest humanoid suffering from cancer, discovered in a tumorous jawbone. Of the Swartkrans discovery, a footbone is all that remains. Since the discovery of Kanam Man diagnostic techniques have greatly advanced with microfocus X-ray computed tomography technology validating earlier hypotheses.

The conclusion reached by two Egyptologists writing six years ago, that cancer's manifestation is a present-day malady resulting from exposure to environmental carcinogens,  not one that persisted in primitive eras forward, appears to have been precipitate, even though in that same year scientists studying bones from two burial sites in Egypt dating to 3200 B.C., along with a German ossuary of between 1400 and 1800, concluded that adjusting for longevity, cancer rates have remained steady for centuries.

It is difficult to discern with any accuracy that malignant tumours elsewhere in the body, representing the full range of the disease, existed to plague humankind when only bones remain after burial, and it is only cancers that afflict the bone that can be studied, since all that is left of human remains is calcified bone.

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