Many cancers employ a sort of genetic smoke screen that allows them to hide from the body’s immune system. One variety of immunotherapy, however, may be able to clear the air. New research into these PD-1 inhibitors highlights them as part of treatment for an aggressive type of brain cancer. Keep reading to learn more, or follow the original story here.
The new findings come from a study by researchers at the University of Colorado Cancer Center. Originally published in Pediatric Blood & Cancer, the study shows how PD-1 inhibitors may be useful in treating supratentorial pediatric ependymoma.
This form of brain cancer is unusual in that the outlook for patients is exceptionally poor. Pediatric cancers, as a whole, have a survival rate of almost 90%. In cases of supratentorial pediatric ependymoma, however, 40% of patients survive fewer than five years after diagnosis.
The tumor occurs in the upper brain regions. Two genetic factors cause the tumor to grow. The study currently discussed focuses on tumors connected to mutation in the RELA gene. Improperly combined with a partner gene, the RELA gene creates a protein which sends a series of signals through the NF-kB network. This network is thought to be a significant player in many forms of cancer.
While NF-kB amplification is relatively common, RELA fusion appears to be unique. And this unique quality is what gave researchers the idea for a way to defeat supratentorial pediatric ependymoma.
In cases where cancer is connected to RELA-fusion, tumors cover themselves in a layer of PD-L1. This protein allows the tumor to hide from the immune system by deactivating T cells. The introduction of a PD-1 inhibitor disables this “cancer camouflage.”
Recently, a clinical trial of the anti-PD-1 drug nivolumab began with a focus on pediatric brain tumors.
Investigators predict that, in these early steps, benefits to patients will be somewhat inconsistent. The current study may, however, provide clues to which brain cancers are most likely to respond to PD-11 inhibitor treatment.
One researcher describes the study as “backfilling the science.” He describes it as an opportunity to gather information for future studies.
This process, may sound lengthy but it is necessary. One road block to ependymoma research is a lack of reliable cell lines and models. Only several weeks ago was a successful animal model created. The current study, and the upcoming tests with mouse models, will hopefully expose which tumors are most susceptible to treatment with PD-1 inhibitors.