There aren’t many options for consumers who have glioblastoma. These lethal brain tumors are connected to the lowest survival rates after recurrence, at 5% for a five-year period. For the last decade or so, patients have been treated through a combination of surgery, chemotherapy, and radiation. However, this only extends life for an average of four to six months after tumor recurrence, and there is currently no existing therapy that has been shown to be effective after tumors return.
But now scientists believe there is a way to fight glioblastoma and improve survival outcomes. Researchers at the Peter O’Donnel Jr. Brain Institute and Harold C. Simmons Comprehensive Cancer Center say that targeting a brain protein that drives tumor growth may allow for future treatment of all forms of the disease.
"These findings change our fundamental understanding of the molecular basis of glioblastoma, and how to treat it," said co-senior author Dr. Robert Bachoo. "We may have identified a set of critical genes we can target with drugs that are shared across nearly all glioblastomas."
Finding a new therapeutic target
During their studies, the researchers found that certain master proteins in the brain – called neurodevelopmental transcription factors -- are what ultimately drive glioblastoma growth. These proteins are responsible for the activity of hundreds of genes during brain development, but when they don’t do their job then the resulting mutations can cause tumor formation.
Bachoo explains that these gene mutations in the brain initially allow tumors to grow, but the disease becomes beyond control after a certain point.
"Our work shows that the gene mutations which the pharmaceutical industry and clinicians have been focusing on are essential only for starting tumor growth. Once the tumor has advanced to the stage where patients seek treatment, these mutations are no longer required for continued tumor growth; they are in effect redundant," he said.
This new idea counters previous theories by the medical community, which long thought that glioblastoma growth was driven by brain proteins called receptor tyrosine kinase. It also explains why drugs used to inhibit these proteins were ineffective at stopping tumor growth.
Solution still out of reach
Though a solution may be years away, the researchers have suggested using a chemotherapy drug called mithramycin, which has been out of clinical use for years because it can cause liver toxicity in some patients. They conclude that finding a safer and more effective treatment for brain tumor patients will take time, but having a target for treatment is encouraging.
"Our discovery has the potential for the development of a new therapy that may increase survival time for glioblastoma patients,” said Dr. Ralf Kittler.