Malignant
Cancers are the biggest singe killer of Modern Humans living in
industrialized countries and the second commonest death in developing
countries. Many cases of cancer are linked to behaviour or
environmental conditions unlikely to have affected our remote
ancestors, such as drinking, smoking, obesity or exposure to
industrial chemicals or pesticides, and for this reason cancers are
often seen as a modern problem, not one that would have affected
earlier Human and Hominin populations. However cancers are known in a
variety of other higher vertebrates (and, curiously, Hagfish), and
are well known of not common in the fossil record, with the earliest
known example in a Carboniferous Fish, as well as several cases from
Dinosaurs, two from Pleistocene Mammoths, and two instances from
Pleistocene Hominins; a 1.98 million-year-old juvenile specimen of
Australopithecus sediba from Malapa in South Africa with a
spinal lesson attributed to benign osteoid osteoma, and a 120
000-year-old Neanderthal rib from Krapina in Poland showing what
appears to be a case of fibrous dysplasia.
In a
paper published in the South African Journal of Science on 28 July
2016, a team of scientists led by Edward Odes of the School ofAnatomical Sciences and Evolutionary Studies Institute at the
University of the Witwatersrand describe a Hominin metatarsal from
Swartkrans Cave in Gauteng State, South Africa (part of the Maropeng Cradle of Humankind World Heritage Site).
The bone
was first inspected by Ryan Franklin of Archaeological and Historical Conservancy as part of an unpublished PhD study. It is a
Hominin fifth metatarsal with a distinct hemispherical bony mass
located on its proximo-ventral end (i.e. the underside of the foot at
the end of the bone closest to the leg) dated to about 1.7 million
years ago, though it cannot be assigned to a species as the site is
known to produce bones of both Homo ergaster and Paranthropus
robustus, species which could not be differentiated in an
isolated metatarsal even were it healthy. Based upon the visible
pathology of the bone, Franklin diagnosed a possible osteoid osteoma
(a usually benign form of cancer, forming isolated tumours in bone
tissue but not usually spreading), though a full diagnosis was not
possible without damage to the specimen.
Hominin
5th metatarsal, exhibiting a hemi-spherical bony mass located on the
proximo-ventral aspect of the shaft, abutting the cortical bone
surface. P, proximal; D, distal; V, ventral. Odes et al.
(2016).
Odes et
al. we-examined the specimen
using micro-focus X-ray computed tomography at the South African
Nuclear Centre for Radiography and Tomography. This enabled the
formation of a three dimensional computer model of the specimen,
showing its internal structure. The tumour is shown not to be fully
fused with the cortex of the bone, but rather to adhere to its
surface. It has an irregular spongey texture, with a cauliflower-like
appearance. The bone beneath this is covered by a thin layer of new
bone with a granular texture and numerous small lessons. The
medullary cavity of the bone is largely infilled by new bone growth.
Such a pattern is typical of malignant osteosarcoma, a rapidly
developing form of bone cancer that is most commonly found in fast
growing areas of the long limb bones, but which is occasionally seen
in the metatarsals.
The
precise course of maligant cancers can be hard to determine even in
living Humans,so determining a precise cause of a cancer in a Middle
Pleistocene individual is likely to be impossible. Cancers are often
thought of as being modern diseases, brought about by lifestype
choices or environmental factors beyond the experience of our earlier
ancestors. However some environmental factors associated with cancer
today were available in the Pleistocene, such as the radiation in
sunlight or radioactive material in granitic rocks. Cancers have also
been linked to a number of viral infections, including Human
Papilloma Virus, Hepatitis B and C Viruses, Epstein-Barr Virus and Human Immunodeficiency Virus. It is also quite
possible that the cancer could have been caused by some interplay of
genetics, environment and infection no longer present in Modern Human
populations.
See also...
Hominin footprints from 1 500 000-year-old deposits near Ileret in northern Kenya. One of the features that serve to distinguish Modern Humans from our
closest living relatives, the Great Apes, is an upright bipedal stance
unlike that seen in any other Primate. Based upon analysis of...
Hominin rib from Sterkfontein Caves. Sterkfontein Caves is a palaeoarchaological excavation site about 40 km
to the northwest of Johannesburg in Gauteng State, South Africa, which
forms part of the Maropeng Cradle of Humankind World Heritage Site
has previously produced a large volume of early...
Dating the Haasgat Cave Deposits. The Malmani Dolomite to the west of Johannesburg and Pretoria is host to
a large number of cave systems that have formed from about 5.3 million
years ago onwards. These caves are noted for a large volume of
fossiliferous material, including many Hominin (species more closely
related to modern Humans than...
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