Casper the Friendly Cancer-Fighting Zebrafish

We all know Casper as the Friendly Ghost who flies around with Wendy. But what does this lovable ghost have to do with finding new cures for cancer?

The answer is zebrafish. For years, scientists have been using zebrafish as model organisms for a variety of different conditions, such as growth and development, neurodegenerative disease, and diabetes (Heath, 2013). Since they are small and reproduce quickly, they are ideal for keeping in a lab (Heath & White, 2013). Additionally, they are perfect for studying development, as their eggs grow outside of the mother (unlike mice), but are still vertebrates and, thus, are similar to humans.

Casper zebrafish. Photograph courtesy of Dr. Paul Frankel (University College London) and Prof. Paul French (Imperial College London).

Casper zebrafish. Photograph courtesy of Dr. Paul Frankel (University College London) and Prof. Paul French (Imperial College London).

Zebrafish are naturally transparent during the embryo and larval stages (Heath & White, 2013), but scientists have now taken this transparent property one step further. Typically, as zebrafish larvae grow and develop, they gain pigmentation. Dr. White and his research team at Boston Children’s Hospital have stopped this pigmentation by “knocking out” specific genes, keeping adult fish transparent (White, 2008). This is useful for watching how the fish, and tumors, develop. The heart, brain, lateral vessels, and intestinal tube can be easily seen in these clear fish (White, 2008).

The new zebrafish was playfully named after the friendly cartoon ghost. This development opens up many new areas for study since more diseases affect adults than children; the model allows researchers to see development into the adult stage. Their transparency allows scientists to monitor a disease without having to harm the organisms. This means that scientists can watch long-term progressions of illnesses. Recently, the focus has shifted to cancer research.

The Ideal Model Organism

What are the qualities of an excellent model organism? One that is small, inexpensive, and similar enough to humans to model diseases; one that easily replicates for additional trials; and one that contracts the same disease of study in a similar manner as humans.

These are some of the many reasons that the zebrafish, or Danio rerio, is seen as an ideal model organism for cancer research. They are small and, thus, many can be tested in small lab spaces. They also reproduce weekly and produce 100-200 embryos each time they mate (Heath & White, 2013).

Cancer-Fighting Fish

One in two men and one in three women will develop cancer in his or her lifetime (“Lifetime Risk,” 2012). Everybody probably knows someone who has suffered from the disease. Cancer does not have a singular cause. It can appear in various places throughout the body and develops differently based on where it is located. Some cancers have a genetic component, while others are purely the result of environmental factors. However, all involve out-of-control cell growth (“What is Cancer?”, 2012). Much progress has been made in recent years involving understanding this disease and finding new treatments. However, we are still a long way from eradicating cancer.

A zebrafish with a tumor (red). Photograph courtesy of Dr. Paul Frankel (University College London) and Prof. Paul French (Imperial College London).

A zebrafish with a tumor (red). Photograph courtesy of Dr. Paul Frankel (University College London) and Prof. Paul French (Imperial College London).

Scientists now believe that the Casper zebrafish may hold the key to gaining a better understanding of how cancer moves and changes, which could provide insight into how to create better treatments. Scientists were even able to inject the fish with pigmented melanomas and watch the cancer grow and metastasize (Heath & White, 2013).

Additionally, cancers can be purposefully triggered by slight changes in a fish’s genes. Researchers are now able to easily microinject early stage zebrafish embryos with the gene of interest in the form of DNA or mRNA. The fish then grow and develop and can pass on the injected gene to the next generation (Heath, 2013). This technique could be used to examine the genetic component of cancer or other hereditary conditions, such as Alzheimer’s or Inflammatory Bowel Syndrome (IBS) (Newton, 2008).

Another feature of these magical fish is that they develop cancer is the same way that humans do. Cancers in zebrafish “often share common genetic underpinnings” with human versions of the disease (Heath & White, 2013). Zebrafish also develop specific cancers in the same areas that humans do. For example, a tumor of intestinal cancer would develop in the fish’s gut just as it would in a human’s. This makes studying patterns of growth easier, as scientists know where to look for the cancer, and gives a more accurate idea of how the fish’s cancer relates to its human counterpart.

A Cure For Cancer?

As of now, this new model organism holds great promise for the future of cancer research. There are only a few possible disadvantages to using Danio rerio as a model organism. First, as with all model organisms, they are not physiologically identical to humans. Additionally, some genes have more than two copies, making it difficult to determine genetic functions or correlations (Ali, Champagne, Spaink, & Richardson, 2011).

And although there will probably never be an umbrella panacea for all cancers, scientists seem to be heading in the right direction. Hopefully, by using research tools like the Casper zebrafish, we may be much closer to finding future treatments and cures for a wider variety of cancers. Maybe one day, curing cancer will be as easy as waving Wendy’s wand.

Works Cited

In Brief:

  • Both men and women have a high risk of developing some form of cancer during their lifetimes
  • Zebrafish are ideal model organisms for developmental studies because their embryos are transparent
  • Researchers at Boston Children’s Hospital have developed a transparent mutant zebrafish commonly known as the “Casper” zebrafish that allows scientists to watch cancers develop in adult fish

This article was written by cYw9. As always, before leaving a response to this article please view our Rules of Conduct. Thanks! -cYw Editorial Staff


Author: cYw9

“Hey! I am super excited to have the opportunity to write articles for cYw! I love all things biology and was thrilled to research amazing model organisms. I recently graduated from a STEM vocational school, which focuses on Biotechnology. I am planning on going to college in the fall, hopefully double majoring in biology and an interdisciplinary concentration involving anthropology, neuroscience, environmental science, and geology. In my spare time, I enjoy creating and appreciating art as well as reading and researching science. I’m also very involved in school and volunteer in both my school and local communities.”

Share This Post On


  1. Avatar

    Great article, thanks!

    Post a Reply
  2. Avatar

    After reading this article I learned quite a few cool, interesting and new facts. The Little white Casper the Friendly Cancer-Fighting Zebra fish reproduce rapidly. However it horrible to think of what the scientists are doing to these poor little amazing fish. The are injecting a Zebra fish with cancer and testing on them to try to find a cure to cancer. On the other hand it is better if a few fish die to stop hundreds of thousands of people dying each year from cancer.

    Post a Reply
  3. Avatar

    #curiousYOUNGwriters What an interesting article regarding zebrafish in the act to fight cancer and other hereditary conditions.

    Post a Reply
  4. Avatar

    #zebrafish_cancer Casper the zebra fish can be a sufficient source for finding deadly tumors of cancers.

    Post a Reply
  5. Avatar

    After reading this article I was able view cancer in a new way. I have always thought of cancer as a disease that effects chiefly humans. However, I am now aware that not only can it effect animals such as the Zebra fish, but due to this it can provide insight on a means to a cure. Would anyone happen to know if the Zebra fish is able to develop all types of cancers that humans can, or is it a select few?

    Post a Reply
  6. Avatar

    Before I found the article on ZebraFish being used in cancer research, I had no idea that fish were so similar to humans that they could be used to monitor other diseases. It was also extremely interesting to see that science has become so advanced, we are able to make fish certain species translucent. Is this process of changing the genetic structure an animal during the early stages of life being implemented elsewhere? Is this is possible with mammals or even humans? Overall, this was a very informative article. Thank you. #curiousYOUNGwriters #sciencewriting #zebrafish #cancer #translucent #casper_the_friendly #STEM #research #science

    Post a Reply
  7. Avatar

    A very interesting article! I was never aware that animals such as the Zebra fish were capable of developing cancer. This article brought new light on the experiments being done to find the cure for cancer. I found it very fascinating to see that scientist were able to create a transparent Zebra fish where they could watch as the cancer developed and how it developed. Would anyone happen to know if the Zebra fish has the capability to develop all the same kind of cancers as humans, or if they can only get a select few?

    Post a Reply
  8. Avatar

    Cancer has been around for a long time and has affected many lives, including my own. My grandmother passed away from lung cancer. It was a horrible death and caused a great deal of pain and mourning in my family. I am elated to see that advancements are being made in the long and arduous battle against all types of cancer. What I though was engrossing was scientists ability to turn Zebrafish translucent. It would be interesting to read more about this and what the exact process is in removing pigmentation genes. This fascinating scientific improvement makes me wonder where else it could be applied. Being able to study the interactions of different organs and organ systems in another animal like a horse or a shark would not only be amazing, but it would also decrease the need to kill animals to study their internals. I understand that many people advocate for the fair treatment of animals and killing them, at times, seems brutal and unjust. This can relate to our STEM class as we are studying mammalian rats. I can only imagine being able to witness the blood flow through its veins. This advancement can aid in the fight against cancer and improve and benefit in future technological advancements in other biomedical fields.

    Post a Reply

Submit a Comment

Your email address will not be published. Required fields are marked *