Home' Trinidad and Tobago Guardian : October 12th 2015 Contents A26
body & soul
Guardian www.guardian.co.tt Monday, October 12, 2015
Cancer is much less common in elephants than
in humans, even though the big beasts bodies have
many more cells. That s a paradox known among
scientists, and now researchers think they may have
an explanation---one they say might someday lead
to new ways to protect people from cancer.
Compared with just one copy in humans, elephants
cells contain 20 copies of a major cancer-suppressing
gene, two teams of scientists report. The gene helps
damaged cells repair themselves or self-destruct
when exposed to cancer-causing substances.
The findings aren t proof that those extra p53 genes
make elephants cancer-resistant, but if future research
confirms it, scientists could try to develop drugs for
humans that would mimic the effect.
Dr Joshua Schiffman, a paediatric cancer specialist
at the University of Utah who led one of the teams,
began his research after hearing a lecture a few years
ago about Peto s paradox. That refers to the fact that
large animals including elephants and whales, have
comparatively low cancer rates even though they
have many more cells than smaller species. Cancer
involves uncontrolled cell growth.
The lecture speaker mentioned that elephants
seemed to have extra copies of the p53 gene. Schiff-
man s patients include children with incomplete p53
genes because of a condition called Li-Fraumeni syn-
drome, which greatly increases their chances of devel-
oping cancer. So Schiffman sought to find clues from
the blood of eight elephants, Ringling Bros. circus
animals and local zoo animals.
His team---as well as a second group of scientists---
pinned down the size of the elephants surplus---20
copies. The second team found many other species
have only one copy, just like humans.
Schiffman and his colleagues compared how ele-
phant cells reacted to radiation, compared with cells
from ten healthy humans and ten patients with Li-
Fraumeni syndrome. The elephant cells self-destructed
at twice the rate of healthy human cells and more
than five times the rate of cells from patients with
the syndrome. Cells that don t self-repair or self-
destruct when exposed to carcinogens become prone
to developing cancer. The work was published recently
in the Journal of the American Medical Association.
Schiffman s team also analysed necropsy data and
Why is elephant cancer rare?
Answer might help treat humans
YOUR DAILY HEALTH
News and Advice
found that elephants sometimes live as long as
humans, yet only about one in 20 die of cancer,
versus about one in four humans.
The second group of researchers, working with
frozen zoo specimens, looked at more than 60 other
species and found only elephants and wooly mam-
moths, their extinct relatives, had extra copies of the
cancer-suppressing gene. This team inserted ele-
phants p53 genes into mouse cells and found that
those cells behaved just like elephants and self-
destructed when exposed to DNA-damaging drugs,
said co-author Vincent Lynch, an evolutionary biol-
ogist at the University of Chicago. (AP)
In this October 1
crosses a road
Cancer is much
less common in
in humans, even
though the big
more cells. A
Fresh research at Sahlgrenska Academy has found
that antioxidants can double the rate of melanoma
metastasis in mice. The results reinforce previous
findings that antioxidants hasten the progression
of lung cancer. According to Professor Martin Bergö,
people with cancer or an elevated risk of developing
the disease should avoid nutritional supplements
that contain antioxidants.
Researchers at Sahlgrenska Academy, University
of Gothenburg, demonstrated that antioxidants has-
tened the progression of lung cancer. Mice given
antioxidants developed additional and more aggressive
tumors. Experiments on human lung cancer cells
confirmed the results. Found in many nutritional
supplements, antioxidants are widely marketed as a
means of preventing cancer. Because the lung cancer
studies called the collective wisdom into question,
they attracted a great deal of attention.
The follow-up studies at Sahlgrenska Academy
have now found that antioxidants double the rate of
metastasis in malignant melanoma, the most perilous
type of skin cancer. Science Translational Medicine
published the findings on October 7.
to metastasise faster
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