A relative of the rabies virus blended with human melanoma DNA eliminated tumors in 60% of mice over about three months, as part of a potentially groundbreaking preclinical trial fueled by research led by the Mayo Clinic. Consider the implications here: Scientists essentially used cancer cells to boost the immune system's response in order to kill cancer.
The Mayo Clinic team, working with colleagues at the University of Leeds in the U.K., touted their technique as something new, combining a genetically altered version of the vesicular stomatitis virus with a wide spectrum of melanoma cancer cell genes into a vaccine that hits the tumor itself. Quite simply, the vaccine is designed to make the cancer cells more visible to the immune system, training it to attack and defeat them. The idea, they explain, is that the immune system is highly resistant to the vesicular stomatitis virus. It reacts to the modified virus, which then displays a wide variety of cancer-related antigens that should be eliminated. Ordinarily, the researchers note, tumors don't show that many antigens on their own, reflecting a vexing genetic ability to adapt to the immune system and avoid its wrath.
"We believe that this new technique will help us to identify a whole set of genes that encode antigens that are important in stimulating the immune system to reject cancer," Mayo researcher and co-author Richard Vile said in a statement.
The idea of training the immune system to better recognize and defeat a cancer through an immunotherapeutic vaccine is a profound one that researchers have struggled with for years. We have the Mayo Clinic asserting that this time is different, compared with previous immunotherapy research that hasn't been able to isolate a large number of tumor cell antigens. While 60% of mice in the test showed progress, 40% did not--which may ultimately leave such a treatment helping some patients but not many others, even if it reaches human testing and approval.
Meanwhile, the Mayo Clinic is plowing ahead, and envisions further studies that could test lung, brain and other more aggressive cancers. For more details on their melanoma vaccine research, read the journal Nature Biotechnology.
- here's the release
- read the journal abstract