Polio virus successfully shrinks brain tumor

Injecting someone with a virus in order to cure brain cancer may sound surprising, but it also may be the cancer treatment of the future. Although still at the beginning of their research, scientists at Duke University have successfully used the polio virus to treat brain tumors. Each year, eight out of every 100,000 persons in the United States are diagnosed with primary malignant brain tumors, representing about two percent of all cancers diagnosed. Primary brain tumors localize in the brain and rarely travel to other parts of the body. Brain tumors that are considered “malignant” are life-threatening and invade the normal brain tissue that surrounds it, growing rapidly. Malignant brain tumors may also spread to the spine. Brain tumors are caused by an abnormal change in the cells’ genes. In most cases the cause is unknown and could have resulted from a complex set of circumstances. This change in the structure of the genetic material is thought to result from inherited genes, environmental factors or even just a random mutation. Gliomas are specific types of tumors that occur within the brain and are the most commonly diagnosed brain tumors. These tumors are thought to arise from glial tissue, which has the role of supporting and nourishing the brain tissue. They are graded I (most optimistic outlook) to IV (most malignant) based on their microscopic appearance. The grade is indicative of their malignancy; growth rate, blood supply, presence of a necrotic center, invasive potential and similarity to normal cells are taken into account. Glioblastomas are grade IV tumors that are highly aggressive, growing rapidly and spreading quickly to other parts of the brain. Early symptoms depend upon the region of the brain that the tumor invades. Sometimes glioblastomas are discovered only when a brain scan is done for some other unrelated reason. These tumors are difficult to treat because they are composed of different types of cells that may or may not respond to certain types of therapies. Also, the tumors commonly contain finger-like projections, which make surgical removal particularly challenging. Once diagnosed, brain tumors can be treated by several methods. Tumors may be removed during an open skull surgical procedure called a craniotomy; however, if the tumor is located in an inaccessible location or near critical structures, a surgical procedure may cause damage to other areas of the brain. Stereotactic radiosurgery is a technique using Cobalt-60 radiation to damage the tumor cells to the extent that they are unable to reproduce and perform their cellular activity. Radiotherapy uses multiple treatments of radiation from linear accelerator machines. Chemotherapy employs pharmaceutical medicines to kill abnormal cells. However, many are plagued with toxic side effects so sometimes the treatment regime consists of a combination of methods. Recently, a new, radical treatment method for brain tumors has been introduced by the Preston Robert Tisch Brain Tumor Center. The idea of employing viruses to attack cancer tumors has existed for over 100 years. However, only recent advances in the application of genetic engineering to these viruses have made the practical use of this technology a reality. Dr. Matthias Gromeier is a molecular biologist at Duke University and has been working on the application of viruses to treat cancer tumors for 25 years. He has developed a method to slightly alter the virus by removing the part of its genetic material that makes it harmful to normal cells. Then, the virus can only make more copies of itself using the only other cells around — the cancer cells. During this process, it kills the cancer cells and leaves the normal surrounding cells unharmed. These “oncolytic viruses” are therefore altered so they only infect and kill cancer cells. Stephanie Lipscomb, a 23-year-old nursing student from South Carolina, was the first patient to receive a successful oncolytic virus treatment for her brain tumor. Lipscomb was diagnosed with a stage IV glioblastoma when she was 20 years old, and doctors predicted she would only have two years left to live. She underwent surgery, chemotherapy and radiation therapy. The tumor reoccurred each time. In 2012, Lipscomb underwent an experimental treatment at Duke University Medical Center. Doctors there injected a genetically modified polio virus directly into her brain tumor. The entire procedure took over six hours. The tumor began to shrink, disappeared and has not returned to date. There is no sign of a tumor in Lipscomb’s brain now, and the word “cured” is being used by some of her doctors. While this new treatment modality is promising, researchers at Duke caution that much more work is needed before it can become routine. For Stephanie Lipscomb, however, it is a lifesaver.