General Information on Brain Tumors

Malignant brain tumors account for a significant portion of solid tumor mortality that has devastating effects on the economy and society.  There are approximately 200,000 brain tumors diagnosed in North America each year, of which 50,000 originate in the brain and 150,000 metastasize from extracranial tumors.  Brain tumors are the leading cause of cancer-related death in children.  Glioblastoma multiforme (GBM) is the most common primary brain tumor, claiming over 12,000 lives annually in the United States. Despite recent progress in surgery, radiotherapy, and chemotherapy, the two-year survival rate for GBM patients remains below 27%.   The side effects from this kind of combination therapy vary, but can be severe and often debilitating. However, other primary brain tumors such as meningioma can typically be treated successfully with surgery alone.  To learn more about the different kinds of brain tumors it may be helpful to visit webpages of the various government agencies and private brain tumor foundations (see links below).

 

Learn About Our Research Program

The long-term goal of our research is to change these disappointing statistics by developing safe, less toxic, therapies for treatment of the most malignant forms of brain cancer.  We are actively investigating several experimental therapies because it is most likely that a combination of several agents will someday lead to a cure for malignant brain tumors.

  • Immunotherapy – vaccines are developed in order to stimulate an anti-tumor immune response that can lead to potent, targeted tumor cell death. These will probably be most effective in the context of residual tumor that remains after surgery.  Our work and the work of others has shown that vaccines can lead to the generation of antibody and T cell responses to kill tumor cells.  A major benefit to vaccination is that side effects have typically been mild and delivery is simply injection beneath the skin.
  • Gene Therapy – tumor cells or normal cells are genetically engineered to secrete proteins that stimulate an anti-tumor immune response, inhibit tumor cell growth directly, or inhibit the growth of blood vessels into the tumor.  A major challenge of gene therapy is to develop technologies that “hit” enough of the target cells to have a strong therapeutic effect.  Overcoming such delivery obstacles may lead to successful gene therapy for brain tumors in the foreseeable future.
  • Drug delivery – both gene therapy and drug therapy suffer from limited delivery of therapeutic agent into the tumor. For gene therapy and direct injection of drugs into the tumor we developed hollow fiber catheters.  Hollow fiber catheters can be placed directly into the brain tumor by a neurosurgeon, followed by a slow continuous infusion of therapeutic agent (also known as convection enhanced delivery).  For small molecule drugs that are administered intravenously, the blood brain barrier excludes most of the drug from reaching the “migratory” tumor cells that travel away from the main tumor mass.  Efflux inhibitors are drugs we are testing that temporarily inhibit the “pumps” in the blood brain barrier responsible for drug efflux.
  • Small Molecule Drug Therapy – brain tumors cells often depend on aberrant progrowth signals to continue growing.  Such progrowth signals can be provided from a cell surface proteins called receptor tyrosine kinases that brain tumor cells produce at abnormally high levels.  A new class of small molecule drugs, known as receptor tyrosine kinase inhibitors (RTKIs) are being developed and tested for treatment of brain cancer.  Our focus is to determine the optimal combination of RTKIs to use in combination with other adjuvants therapies to kill brain tumor cells while sparing normal cells.

     
Latest News

  • Dr. Ohlfest speaks to NY times about comparative oncology
  • University of Minnesota to Host Brain Tumor Symposium
  • Human Clinical Trial and Dog Trial on CBS news
  • Touching story: our human patient meets our dog patient
  • Minnesota Public Radio gives update on human clinical trial

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