Malignant tumour found in 1.7m year old
metatarsal
Cancer
is the primary cause of death in industrialised countries and the second most
common cause of death in the developing world. The condition not known to occur
in non-chordates and is largely confined to the higher vertebrates. It is
extremely ancient, with purported cases of neoplasm found in fossil fish from
the Upper Devonian. It may therefore be assumed that hominins have always been
afflicted by cancer, but evidence for malignant tumours is rare in the fossil
record. The earliest example affecting an archaic human is a case of fibrous dysplasia
from a Neanderthal rib dated to 120,000 years ago from the site of Krapina in
northern Croatia.
The
earliest evidence yet described for malignant bony tumours in the hominin
fossil record has recently been announced by a South African team. They found definite
evidence for a malignant tumour in a hominin fossil designated SK 7923: a left
fifth metatarsal from the cave site of Swartkrans in the Cradle of Humankind,
South Africa, dating to between 1.6 and 1.8 million years old. The exact
species has not been determined, but the site has previously yielded fossils of
Paranthropus robustus and Homo erectus.
The
tumour was identified as an osteosarcoma, a rare primary bone cancer which in modern
humans usually affects younger people. Early diagnosis and treatment can effect
survival rates of 60 to 80 percent, although until the 1960s the outlook was
very poor. It was not clear how old SK 7923 was at death, or whether the cancer
was the cause of death, but the cancer would have affected their ability to
walk and run – which by itself could have ultimately proved fatal.
The
same team also reported a benign bone tumour affecting the juvenile Australopithecus sediba MH 1 from
Malapa, dating to 1.98 million years ago.
It
is often assumed that both malignant and benign tumours in humans are the
result of modern lifestyles and environments, but these results show that they
occurred in our ancient relatives millions of years before modern industrial
societies arose.
References:
Odes, E. et al.,
Earliest hominin cancer: 1.7-million-yearold osteosarcoma from Swartkrans Cave,
South Africa. South African Journal of Science 112 (7/8) (2016).
Randolph-Quinney, P. et
al., Osteogenic tumour in Australopithecus sediba: Earliest hominin
evidence for neoplastic disease. South African Journal of Science 112
(7/8) (2016).
