St. Jude researchers identify retinoblastoma-causing cell

MEMPHIS, Tenn. — Researchers have identified the cell that gives rise to retinoblastoma, according to a press release from St. Jude Children's Research Hospital. Certain mutations enable these cells to multiply, causing the cancer, according to the release.

Michael Dyer, PhD, and colleagues reduced the activity of the Rb family of genes in the retina of mouse models. Once this activity was reduced, the researchers observed that fully differentiated horizontal neurons multiplied without losing the differentiated features of normal horizontal neurons, the release said.

The finding shows that retinoblastoma can arise from fully formed, matured horizontal interneurons, disproving the principle that such nerves cannot multiply like young, immature cells, according to the release.

"For the past 100 years, it's been ingrained among scientists that differentiated mature nerves are so elaborate that they can't divide, and if they try to divide, they undergo cell death," Dr. Dyer said in the release. "This is the first time that anyone has shown that under certain conditions, a fully mature and differentiated nerve can undergo cell division and multiply."

Additionally, the finding suggests that "it may one day be possible for scientists to induce fully developed neurons to multiply and coax the injured brain to repair itself," the release said.

The study is published in the Oct. 19 issue of Cell.