New study contradicts conventional wisdom on cancer therapies
Therapeutic vaccines against cancer have received a great deal of attention, but their results have been mixed. The vaccines typically contain a cancer-specific protein fragment, or peptide, that is injected into a patient. For the vaccine to be effective, the patient's immune system must then recognize the peptide as an invader to be attacked. This stimulates the production of anti-cancer T-cells, according to NPR.
Willem Overwijk, lead author of the study, suggests that while the vaccines may trigger an increase in T-cell production, those cells may not be able to find their way to tumors. Overwijk is an assistant professor at M.D. Anderson Cancer Center in Houston, and his study was published in the latest issue of the journal Nature Medicine.
Cancer vaccines also typically include an adjuvant called IFA, which is short for incomplete Freund's adjuvant. IFA is typically added to boost immune response. Overwijk said IFA is thought to be helpful because it consists mainly of a mineral oil that is not biodegradable in the human body and will continue to provoke a response, according to NPR.
During the study, however, the mice T-cells went straight for the site of the injection, not the tumor.
"The body doesn't know how to deal with the mineral oil [in IFA], and the body cannot get rid of that big blob of vaccine... that sits under the skin," Overwijk said, NPR reports. "The T-cells go back and try to kill the oil, but they can't."
Overwijk said if his finding is supported in human research, it could shift a fundamental approach to making cancer therapies. The majority of the approximately 90 therapies undergoing clinical trials use IFA.