Newswise — When removing a cancer tumor, doctors often must cut into healthy tissue to make sure they have removed all of the cancerous cells. While this is acceptable when a tumor is lodged in a leg, tumors that reside in the brain or other delicate areas can create a dilemma for surgeons. Removing healthy brain cells could result in substantial damage, but a University of Missouri-Columbia veterinarian believes he might have the answer.
Peter Gordon, an MU veterinary resident, is working with terminally ill dogs to discover whether a special water-based compound can distinguish between brain tumor cells and healthy cells during surgery. Gordon's challenge is to find the right chemical that will highlight all of the cancerous cells, while not touching the healthy cells.
"Currently, doctors will inject a contrast agent into the patient and follow the injection with an MRI or CT scan," Gordon said. "This technique allows the doctor to see the approximate location of the tumor and outlying cancer cells, but we don't have the ability to do this while the surgery is taking place."
Currently, Gordon is testing sodium fluorescein, a compound that highlights tumor cells, to identify the cancer. The brain's blood supply is surrounded by a layer of cells called the blood-brain barrier. This barrier protects the brain against many dangerous chemicals or molecules. When a tumor begins to grow, it creates leaks in the blood-brain barrier allowing in a variety of compounds, including those that might be dangerous to the brain. However, Gordon discovered that sodium fluorescein also can get through the barrier where the tumor has created holes.
Gordon's preliminary findings indicate that once through the barrier, sodium fluorescein accumulates in the area of the tumor cells. The next step is to illuminate the brain with a special blue light. Under normal surroundings, sodium fluorescein is invisible, but when illuminated under cobalt blue light, the compound releases a green light, thus identifying the cancerous cells, while keeping the healthy cells in the dark.
"So far, we have proven that the fluid will not identify healthy tissue and that's a step in the right direction," Gordon said. "Now we need to make sure that all of the cancer cells are illuminated. While it's important to make sure we don't take any healthy cells, it is just as important to make sure that we eliminate all the cancerous cells."
Gordon's research is funded by a grant from the Scott Endowed Program in Veterinary Oncology in the Department of Veterinary Medicine and Surgery.
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