Retinoblastoma is the third most common cancer in infants after leukemia and neuroblastoma (nerve cancer). Retinoblastoma that has spread outside the eye is among the deadliest childhood cancers, with an average survival rate of less than 10 percent. Until now, researchers had no reliable animal model in which to test new drugs that might improve the outcome of retinoblastoma in children. However, using this model and two other mouse models developed in the same lab at St. Jude, researchers have already tested effective new drugs and drug combinations that will be used in future retinoblastoma treatments, according to Michael Dyer, Ph.D., assistant member in the St. Jude Department of Developmental Neurobiology. Dyer is senior author of the Cell Cycle report.
The need for new treatments is especially critical for children with bilateral retinoblastoma, cancer in both eyes. Much effort is focused on saving vision in these children by eliminating the cancer using chemotherapy and intensive focal treatments with lasers and cryotherapy, which means killing cancer cells by freezing them. The main goal of these treatments is to save the eyes and, if possible, to avoid or delay radiation therapy. Unfortunately, in many cases, one or both eyes must be removed if other treatments fail. Effective drug therapy would greatly improve both the chance of survival among these children as well as preserve their vision.
A key genetic defect in both children and the St. Jude retinoblastoma mouse is the lack of Rb1, the first tumor suppressor gene identified in humans. The St. Jude model is called a "knockout" because researchers elimin
Contact: Bonnie Cameron
St. Jude Children's Research Hospital