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the antlers of deer moose and elk grow
ridiculously fast uniquely fast actually
among mammals they're the only body
parts that can regenerate completely and
they do regrowing year after year from
just a small stump so you would think
with all those cells whose job is to
divide really fast that animals in the
deer family would get cancer more often
than others but do you actually get
cancer less weigh less like one-fifth as
often as other mammals at least based on
statistics from animals in captivity and
a massive 2019 genome study might have
revealed why and a paper published in
the journal Science researchers analyzed
the genomes of certain species of deer
along with dozens of related species and
the genetic changes they found in the
deer DNA go a long way towards
explaining both how antlers grow so fast
and how that growth doesn't lead to
cancer more often usually cells growing
and dividing too fast as a problem when
cell growth escapes the body's control
those cells can form a tumor cancer is
what happens when those uncontrolled
cells become malignant capable of
escaping to other parts of the body and
causing extra cell division there too
with their super fast growth antlers
bear some resemblance to tumors in fact
the 2019 study found that in terms of
what genes they express antler cells are
more like bone cancer than regular bone
that includes genetic changes that
promote cell growth and division and
based on what we know from studies and
other species similar changes can often
cause cancer if left unchecked for
example antler cells Express a lot of a
gene called Foss meaning they contain
more of that genes protein product than
you'd normally expect and Foss instructs
cells to grow and divide more that
should be a big risk cancer wise usually
it takes a bunch of problematic genes
working together to cause cancer but in
mouse studies overexpressing just this
one gene is enough to cause bone cancer
any cancer biologist will tell you that
Foss is really really mean and deer
strongly Express Foss and a bunch of
other genes that can lead to cancer but
it turns out deer also have genetic
changes to keep all that extra cell
division from turning into cancer mainly
involving p53 sometimes known as the
master tumor suppressor p53 makes a
protein that checks cells for DNA damage
if the damage is fixable the p53 protein
tells the cell to
parrot if it's not fixable it makes the
cell self-destruct elephants which also
have very low cancer rates have extra
copies of the p53 gene in their DNA
researchers think that's a big part of
what makes them less prone to cancer
deer don't have extra copies instead
they've evolved more genes to support
what p53 does and help it along they've
also evolved a bunch of other tumor
suppressor genes specifically expressed
in their antlers the researchers suggest
that these two sets of genetic changes
might have evolved together growing
antlers help attract mates which was
good because babies but it also involved
genetic changes that led to super fast
cell division which was bad because
cancer in the end they evolved a complex
set of mechanisms to let antler cells
grow and divide really fast while
keeping everything tightly controlled so
scientists seem to have their answer to
why deer don't get cancer more often and
the hope is that maybe with more
research into these mechanisms we'll get
a little closer to preventing cancer in
humans too thanks for watching this
episode of scishow and thanks to our
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