Mr. Frosty: a Gecko Teaching Us About Skin Cancer

Tumor formation & the unique colorings of Lemon Frost Geckos, such as Mr. Frosty, have given us a unique look into skin cancers that largely impact humans. Keep reading to learn more!

Sections:
  1. About Mr. Frosty & His Kind
  2. Research on Mr. Frosty
  3. What Mr. Frosty is Teaching Us About Skin Cancer
  4. Implications

(TL;DR and Glossary at the bottom 😊)

Approximate Read Time: 7 minutes!


About Mr. Frosty & His Kind

“How can you not love a story that starts with an animal named Mr. Frosty?”

Leonid Kruglyak, an evolutionary geneticist at UCLA

Mr. Frosty is a Lemon Frost Gecko, which is a rare type of leopard gecko (Eublepharis macularius). 

Mr. Frosty, a Lemon Frost gecko

Leopard geckos are native to the Middle East and South Asia, and leopard geckos — not Lemon Frost Geckos specifically — are a common reptile pet.

It all started in 2017 when Steve Sykes, the owner of Geckos Etc. Herpetoculture, a gecko breeding facility in California, bred a colony of 900+ geckos using Mr. Frosty and various female companions.

Steve Sykes of Geckos Etc. Herpetoculture

Sykes set out with the mission of breeding these beautiful lizards for sale, but before most of the geckos were 5 years old, more than 80% of them had developed curious white tumors. 

A non-Lemon Frost gecko with no tumors
Lemon frost geckos with tumors

Some of the tumors grew so large that they were rupturing, causing infections, and impacting the mobility of the geckos. 

“We’ve stopped breeding lemon frosts, and we have no intentions to start it up again in the future. My goal is to produce beautiful, perfect, healthy geckos. And it doesn’t appear that it’s possible to separate the lemon frost gene from this tumor phenotype.”

Steve Sykes, owner of Geckos Etc. Herpetoculture, a gecko breeding facility in California

Research on Mr. Frosty

It wasn’t long before Leonid Kruglyak, an evolutionary geneticist at UCLA, and Longhua Guo, a geneticist at UCLA, heard about Sykes’ Lemon Frost Geckos and their aptitude for tumor development.

They teamed up, and along with other colleagues, they took DNA samples from both the geckos’ saliva as well as pieces of the geckos’ tails. 

Their research goal? To decipher why so many of these geckos were producing tumors.

Their data consisted of the genetic makeup of

  • ~30 geckos that inherited Lemon Frost gecko traits from both parents
  • 100+ geckos that inherited Lemon Frost gecko traits from only one parent
  • ~40 geckos that do not have Lemon Frost gecko traits

The scientists compared the genetic makeup of geckos with tumors and geckos without tumors, and the mutation causing these tumors in so many of the Lemon Frost geckos became apparent.

“There’s been very little molecular genetic work done in reptiles, and so it’s fantastic to see an instance where a group has been able to track down the genetic basis of a really interesting trait.”

Douglas Menke, a geneticist at the University of Georgia

What Mr. Frosty is Teaching Us About Skin Cancer

The scientists discovered that the tumors and signature pigments in Lemon Frost geckos originate from a common single gene mutation — a mutation on the SPINT1 gene.

It turns out that a mutation on the SPINT1 gene is also known to give rise to the melanoma skin cancer in humans, as well as tumors in zebrafish and mice:

“It turns out that SPINT1 can explain what is going on here because SPINT1 has been reported in zebrafish, in mice and in humans. [Mutations in the gene] are associated with skin-cell tumors.”

Longhua Guo, a geneticist at UCLA

This mutation originates in pigment-producing cells called iridophores, and it likely causes the overproduction of white skin cells, which 

  1. gives the Lemon Frost geckos their characteristic “frosty” aesthetic
  2. makes them more susceptible to developing tumors

“It was extremely exciting that they could link the Lemon Frost characteristics to a specific region of the genome. Studying a gecko is not only about the gecko’s health or about understanding basic biology, but could also provide key information to further research on other organisms, including humans.”

Ylenia Chiari, an evolutionary biologist at George Mason University

Implications

Understanding the mutation in these geckos may help us develop new treatments for melanoma skin cancer and help us more easily diagnose melanoma in humans.

This study also provides further evidence that SPINT1 is responsible for tumor growth in various organisms.

“I do think it will have an impact on cancer research, in that we understand the conservedness of this [SPINT1 genetic] pathway a little bit better now. It will also be a potential new model organism for studying the development of skin cancer and contributing to actual therapeutic development.”

Lara Urban, a conservation genomics research fellow at the University of Otago in New Zealand

Following this study, many questions still remain to be explored:

  1. Why do some Lemon Frost geckos produce more tumors than others?
  2. Why do the tumors on the geckos differ? (slight tumors that remain dormant versus fast-growing active tumors)
  3. Are there tumor suppressor genes that suppress tumors in some geckos?

This study is incredibly exciting, as it provides an additional lens into how skin-cell tumors originate and it has incredible implications for multiple organisms.

What are your thoughts on how Lemon Frost geckos can help us better understand melanoma skin cancer?

Thank you for reading this piece. I hope you enjoyed it & will further ponder the knowledge it brings to light. I encourage you to leave a comment and/or start a discussion in the section below! 

Feel free to contact me at brainsproutblog@gmail.com and follow the blog @brainsproutblog on Instagram or Twitter for updates!


TL;DR

  • Mr. Frosty is a Lemon Frost Gecko, and he was used to breed a colony of 900+ geckos. But before most of his offspring were 5 years old, more than 80% of them had developed white tumors.
  • Scientists collected DNA samples from the gecko colony, and they discovered that the tumors originate from a common single gene mutation on the SPINT1 gene.
  • A mutation on the SPINT1 gene is also known to give rise to the melanoma skin cancer in humans
  • Understanding the mutation in these geckos may help us develop new treatments for melanoma skin cancer and help us more easily diagnose melanoma in humans.

Glossary

  • Cancer: a disease caused by the abnormal and uncontrolled division of cells in a part of the body
  • Iridophores: skin pigment cells
  • Melanoma: a type of skin cancer that develops when melanocytes (pigment cells in the skin) grow uncontrolled
  • Tumor: a swollen part of the body caused by the abnormal growth of tissue

Read more (sources)!

  1. https://www.sciencenews.org/article/lemon-frost-gecko-skin-cancer-tumors-genetics
  2. https://www.scientificamerican.com/article/cancer-clues-found-in-gene-behind-lemon-frost-gecko-color1/ 
  3. https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1009580 
  4. https://www.sciencedaily.com/releases/2021/06/210624141556.htm 
  5. https://www.mbi.ucla.edu/ 

Image Sources

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