St. Jude Identifies the Specific Cell That Causes Eye Cancer, Disproving Long-H...( Researchers found that certain mu...),Health

Researchers found that certain mutations enable specific cells in the retina to multiply and cause eye cancer, a finding that suggests deliberate genetic manipulations might coax an injured brain to repair itself

MEMPHIS, Tenn., Oct. 18 /PRNewswire-USNewswire/ -- Investigators at St. Jude Children's Research Hospital have identified the cell that gives rise to the eye cancer retinoblastoma, disproving a long-standing principle of nerve growth and development. The finding suggests for the first time that it may one day be possible for scientists to induce fully developed neurons to multiply and coax the injured brain to repair itself.

A report of this work appears in the Oct. 19 issue of the journal "Cell." Michael Dyer, Ph.D., an associate member in the St. Jude Department of Developmental Neurobiology, is the report's senior author.

The immediate importance of the St. Jude finding is that it unexpectedly showed that retinoblastoma can arise from fully matured nerves in the retina called horizontal interneurons. This disproves the scientific principle that fully formed, mature nerves cannot multiply like young, immature cells, Dyer said. Human neurodegenerative disorders such as Alzheimer's disease can occur when differentiated nerves in the brain try to multiply, and in the process, trigger a self-destruct program called apoptosis. Differentiation is the process by which cells lose their primitive, stem-cell-like properties that include the ability to grow and multiply, and instead develop specialized shapes and functions.

The St. Jude researchers showed that when the activity of the Rb family of genes was reduced in the retina of mouse models, fully differentiated horizontal neurons could multiply and yet retain all of the differentiated features of normal horizontal neurons including neurites and synapses.

"For the past 100 years, it's been ingrained among scientists that differentiated mature nerves are so elaborate that
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