Key discoveries could shed light on retinoblastoma

Retinoblastoma is a tumor of the retina that generally affects children under 5 years of age and accounts for approximately 4% of childhood cancers. If not diagnosed early, retinoblastoma may result in loss of one or both eyes and can be fatal. David Cobrinik, MD, PhD, of the Saban Research Institute of Children's Hospital Los Angeles, has made key discoveries to advance our understanding of this cancer. His team showed that retinoblastoma arises from abnormal proliferation of a cell type called cones in the retina, the light-sensing layer behind the eye. A mutation in a tumor-suppressing gene called RB effectively releases a brake on cell growth, causing cones to grow out of control and form a tumor. Children who inherit a mutated form of RB have more than a 95% chance of getting retinoblastoma. Given this strong correlation, an understanding of how RB mutations affect cone cells could lead scientists towards an intervention in the disease.

Dr. Cobrinik received a $1.6M grant from the National Cancer Institute of the NIH to study what causes cone cells to proliferate and form tumors. Though the genetic mutation is identified, we still must understand how RB mutation affects cone cells. What makes a cell turn cancerous? Why are cone cells vulnerable to this mutation? To answer these questions, Dr. Cobrinik explains, we must understand the normal function of RB and what it is doing to block tumor formation in healthy individuals. "If we can understand this," Dr. Cobrinik says, "we might have the opportunity to prevent the tumor process." While his research is focused on retinoblastoma, understanding how tumor-suppressing genes affect healthy cells could open up avenues for treatment in many cancer types.