These tanks hold thousands of zebra fish, but if you take a closer look, you'll notice some have lost their stripes. "You can really see inside the animals." Researchers altered their DNA and created transparent fish all in the name of research. "Fish have genes that are amazingly similar to human genes."
Researcher Doctor Richard Mark White transplanted Melanoma into the see-through fish. He now watches how cancer grows and spreads in real time in a living organism. "So we can see the origins of just how a tumor started and how it spreads within the body over time, which is pretty analogous as to what happens in a human: it starts small and gets bigger." Doctor White says the fish prove there's a pattern to the cancer spread -- important in treating humans since the spread of cancer is what kills. "We're sort of realizing pretty quickly that when tumors cells spread they do it on a pretty organized way. It's really an amazing picture of how tumors grow and spread in a very rapid time. in a way, you could never do it in an animal or obviously in a human."
Understanding that organized way could help patients like Heather Fraelick get better treatment to stop cancer from spreading. At twenty five she discovered Melanoma on her arm and later had a recurrence. "I was scared to find out the results from my surgery because I knew that if the melanoma had traveled my odds weren't good for survival."
The goal -- improve those odds and find new treatments, using fish as a window into the body's fight against cancer.
The researchers are also using the fish to learn how to make stem cell transplants safer. Humans and zebra fish share about 80-percent of the same genes.
RESEARCHING A KILLER: It's likely you know someone who has battled cancer and unlikely that anyone you know hasn't been affected by the disease in some way. The National Cancer Institute says in 2005, more than 11 million Americans were alive who had a history of cancer. The American Cancer Society says the personal and financial cost of cancer adds up to $260 billion a year. One recent study suggests research resulting in a 1 percent lower cancer mortality rate would be worth $500 billion -- more than 2.5 times the cost of the disease each year.
SEEING THROUGH CANCER'S MYSTERY: Some researchers are taking that money- and life-saving challenge into the laboratory -- with fish as partners. The zebrafish, a small, striped aquarium fish, has become one of the stars of cancer research. It was first used in biomedical research to study the role of certain genes and genetic mutations. "Fish have genes that are amazingly similar to human genes," Richard Mark White, M.D., Ph.D., Professor of Medical Oncology at Harvard University in Boston, Mass., and a zebrafish researcher, told Ivanhoe. A recent step in zebrafish research involved developing a new, transparent breed of zebrafish called the "casper" to give scientists a literal peek inside how the body works, especially as it battles diseases like cancer. The "casper's" brain, heart and digestive tract are visible, also allowing researchers to study genetic defects of those organs through a fish's lifespan. Before this step, researchers could only study cancer in zebrafish embryos since adults were opaque. To understand better how cancer spreads through the body, researchers now transplant tumor cells into the transparent fish and monitor the cancer's progress. "Initially you do not see anything, and then over the course of five to seven days, you start to see that tumor grow," Dr. White said. "Within a week to ten days, we start to see cells break off and go to other parts of the body."
Scientists like Dr. White are also using zebrafish to learn more about stem cell transplantation and why it sometimes doesn't work. In recent research, Dr. White transplanted fluorescent blood-forming stem cells from one fish to another. After four weeks, the stem cells had visibly migrated and grown in the fish's bone marrow. Researchers could see individual stem cells, something not easily observed in a living organism. By visualizing how stem cells build blood in the zebrafish, scientists can look for ways to help patients replenish their blood faster. "One of the goals is, can we find better pathways or drugs that will make bone marrow transplants far more efficient or more tolerable for patients," Dr. White said. "Bone marrow transplants are a good therapy, but it is an extremely toxic therapy, and we need to find ways to harness stem cells to make that therapy better."
FOR MORE INFORMATION, PLEASE CONTACT:
Jamie Newton
Public Affairs
Children's Hospital Boston
(617) 919-3110
