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Mr. Frosty sounds like a frozen summer treat.
But it’s also the name of a cancer-fighting gecko!
And some people would say that that’s even cooler.
He got his name because of his white and yellow coloring,
a special pattern known as Lemon Frost that is encoded in his genes.
And these colors make geckos like him very sought after.
But it turns out that his beautiful white pigment is produced by cancerous skin cells.
So scientists studied Mr. Frosty and his family and got to the root of
some questions about where skin cancer comes from, even in humans.
Researchers at UCLA bought Mr. Frosty from a gecko breeder to figure out
how these color-producing cells developed and evolved.
And in the process, they were able to figure out
some of the genes that regulate the cancer, making those colorful skin cells.
First, they needed to know how many genes make Lemon Frost colors.
So the UCLA researchers bred Mr. Frosty with some wild type geckos
to see what their babies would look like.
Wild type is the term researchers use to describe a genetically typical animal.
About half of the babies were Lemon Frost geckos, suggesting that Lemon Frost is
the coloration of a gecko with half wild type genes and half mutated genes.
Then, those Lemon Frost baby geckos grew up and were bred with each other.
And the babies from two Lemon Frost parents were about half Lemon Frost,
about a quarter had even more white pigment known as super Lemon Frost,
and about a quarter were wild type.
That spread basically means that Lemon Frost
likely comes from just one mutation in a single segment of DNA.
The researchers also figured out that Mr. Frosty’s Lemon Frost mutation
occurs on a gene that makes a ton of white skin cells when it’s mutated.
And that’s the basic idea of some cancers.
When cells aren’t properly regulated,
your body keeps making more and more of them until it becomes a problem.
As you might imagine, geckos that have
two copies of the mutation develop even more tumors.
Unfortunately, that’s also what makes them stand out
with pretty colors on their skin.
And here’s the thing: You have that same gene
that was mutated in Mr. Frosty’s DNA.
It’s called SPINT1.
Lots of animals have similar genetics,
and it’s not always because we’re directly related.
Sometimes we have a common ancestor.
But other times, we both had similar genetic mutations that
allowed us to develop similar physical features.
It’s called parallel evolution.
And SPINT1 is a gene in humans, as well as in other animals,
that determines if you’ll develop tumors or not.
It carries the genetic code for a protein called HAI-1, which stops growth factors.
Those are the molecules that usually direct cells to either make more of
themselves or not, but HAI-1 stops them from sending pro-growth signals.
So if you have cancer cells that won’t stop reproducing, HAI-1 is a part of the
process that brings them back into check and signals them to reproduce less.
Scientists think this is one way that SPINT1 reduces cancer.
Since HAI-1 is a product of SPINT1’s code, a mutation that changes SPINT1’s
code, like what was found in Mr. Frosty’s DNA, could allow cancer cells to develop.
So SPINT1 is likely to be a big player in cancer development
and regulation in humans and geckos.
Now, not all geckos with this genetic mutation develop malignant skin tumors,
but 80% did in the UCLA study.
Which are not good odds.
See, if you have a mutation in the SPINT1 gene, you don’t automatically
get cancer, just like if you don’t have it you’re not automatically cancer-free.
One way these genes can become more or less influential
is by how often they are allowed to do their jobs.
Sometimes, genes can’t produce what they’re supposed to,
because there’s something blocking them from making proteins.
And if that happens, they end up having less of an impact.
So when SPINT1 can’t make its HAI-1 protein
to help regulate the production of cells, it can result in cancer.
This is what happens to individuals with similar cancers to Mr. Frosty.
Since the SPINT1 and HAI-1 that led to Mr. Frosty’s cancer have also been
found in humans, studying Mr. Frosty and his descendants could
help us understand where some of our cancers come from
and how to stop them from progressing.
In the end, geckos and humans might be able to
help each other fight cancer together.
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