Zeroing in on brain tumors
Scott Pomeroy, MD, PhD, and Todd Golub, MD, have combined their knowledge and research interests in a way that may lead to less toxic and more effective therapies for patients with brain tumors.
Pomeroy, a neurologist who divides his time between seeing patients with brain tumors and hunting down the source of their disease, is using Golub's microarray, or "gene chip" technology, to discover which genes control the growth of brain tumors. The technology measures specific RNA molecules expressed by over 6,000 genes in each brain tumor. RNA performs a variety of signaling functions within normal or cancerous cells, including telling the cell when to divide or when to die. In cancer, gene mutations lead to abnormal RNA patterns, allowing cells to continue dividing when they are meant to stop or to continue living when they naturally were meant to die.
The new array methods have enabled the Pomeroy and Golub teams to sort through hundreds of thousands of data points to identify the specific gene expression patterns characteristic of each brain tumor. They discovered that gene patterns readily distinguish tumors that look different under the microscope, but also, in some cases, can distinguish tumors that typically shun treatment and metastasize from those that respond to treatment even though they appear identical under the microscope. The genes recognized by array analysis also are opening doors to understanding which molecules are responsible for driving the tumor's growth.
"Our realistic hope for the near future is that we will be able to identify highly malignant tumors at the time of diagnosis so we can tailor the treatments we have today," says Pomeroy. "Current treatments involve radiation and chemotherapy, which damage both the tumor and the normal brain. If we are certain a tumor will respond to conventional therapy, we can reduce the dose to spare the normal brain.
"Even when a child's brain tumor is cured, life-changing injuries occur all too frequently, resulting in learning disorders and other disabilities," says Pomeroy. "But microarray technology provides a new understanding of brain tumors that will enable the development of treatments that are more effective and less harmful to the brain, offering new hope for these children and their families."
