ST. LOUIS – Is the best treatment for cancer already inside of us?
Research is underway at Washington University to test a new approach to cancer treatment. Beyond traditional therapies like surgery, chemotherapy and radiation, scientists want to know if the human body’s own immune system can attack tumors.
They’re testing personalized vaccines designed to target deadly cancer cells in each patient. A vaccine is any substance that prevents or treats a disease with properties of the disease itself. Scientists know that fighting fire with fire works for many viruses like flu, measles or polio. Now they want to test that theory with cancer, but since every tumor is different, every vaccine will be different.
Advancements in genetic sequencing, or decoding the DNA of cells, have made it easier to figure out what makes tumors unique. Scientists have found potential targets in tumor cells that could cause them to break down. Now they’re passing that knowledge on to doctors to try out in their patients with the most challenging cancers. Clinical trials are now enrolling patients with melanoma, brain cancer and breast cancer.
The concept is hypothetical. The research is experimental. There is no proof that it works. But after staring down deadly cancers, doctors are intrigued.
Robert Schreiber of Washington University started tests with mice that lacked a critical gene that allowed the immune system to make lymphocytes — white blood cells that defend the body against disease. “What we showed conclusively was mice that had defects in the immune system got tumors more quickly and in higher incidences than normal mice,” Schreiber said.
And with that, the concept of cancer immunology was back. The Center for Human Immunology and Immunotherapy Programs at Washington University launched last year with Schreiber as director to help doctors use the immune system to fight cancer and other diseases. Other medical centers have taken different approaches to cancer immunology. Duke University is working with a polio virus vaccine to induce the immune system to fight brain tumors. The Mayo Clinic is doing a similar trial with a measles vaccine.
Washington University leads the study of personalized cancer vaccines. With help from their genetic sequencing labs, local scientists try to isolate the best antigen targets — or the most dangerous mutated cells — from each patient’s tumor to vaccinate against.
Genetic sequencing creates a search party for “the Achilles’ heel in each patient’s tumor,” said Dr. Gavin Dunn, a neurosurgeon. A clinical trial is underway to test vaccines against the most deadly brain tumors, called glioblastomas. The first patient will get a personalized vaccine in the next few weeks.
Scientists now think vaccines can be used to stimulate the immune system to fight cancers that are formed. But without a known virus or other cause, scientists must figure out what differentiates a patient’s tumor cells from healthy cells. Then they must try to vaccinate against mutations, called neo-antigens, that occur only in the bad cells. “It’s a different answer for every patient,” said Elaine Mardis, director of technology development at the university’s McDonnell Genome Institute.