Transparent Fish Gives New Window ...( Scientists watched as cancer cells sp...),Health

Scientists watched as cancer cells spread throughout living zebrafish's body

TUESDAY, Feb. 5 (HealthDay News) -- Medical researchers can now get a clearer view into human biology and disease with a newly developed, totally transparent breed of zebrafish, a common model for medical research.

According to the Children's Hospital Boston researchers who developed the new breed, zebrafish are genetically similar to humans. This new transparent form of the small fish will provide researchers with a direct view of its internal organs and the opportunity to observe processes such as the spread of cancer or blood production after bone marrow transplant, as they occur in a living organism.

In normal zebrafish, embryos are transparent but adults become opaque. The new permanently transparent fish, created by mating two existing zebrafish breeds, is described in the Feb. 7 issue of Cell Stem Cell.

Currently, researchers studying human diseases in animals induce the illness and allow it to progress, then kill and dissect the animals. But that approach is bound to miss something in cancer and other rapidly changing processes, according to the team that developed the transparent zebrafish.

"It's like taking a photograph when you need a video," Dr. Richard White, a clinical fellow in the Stem Cell Program at Children's Hospital Boston and an instructor of medicine at the Dana-Farber Cancer Institute, said in a prepared statement.

In his first experiment with the transparent zebrafish, White viewed how cancer spreads.

"The process by which a tumor goes from being localized to widespread and ultimately fatal is the most vexing problem that oncologists face," White said. "We don't know why cancer cells decide to move away from their primary site to other parts of the body."

He placed a fluorescent melanoma (skin cancer) tumor in the abdominal cavity of a transparent zebrafish and, using
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