When cancer cells hide in plain sight, they become much harder to beat. Now, scientists in Singapore have found a crucial on/off switch that cancer cells use to stay invisible to the body's defenses — a discovery that could lead to better treatments for many types of cancer.
Researchers at the Cancer Science Institute of Singapore, part of the National University of Singapore, discovered that a protein called DDX6 acts like a hidden cloak for cancer cells. Normally, the immune system constantly patrols the body looking for abnormal cells, keeping watch for warning signals called double-stranded RNA — the kind of molecule that appears during viral infections. When cancer cells produce these signals, the immune system should attack them.
But many cancers have figured out how to silence these alarms. The Singapore team found that DDX6 teams up with another protein called ADAR1 to suppress the warning signals, essentially helping tumors stay hidden. The researchers call DDX6 a "hidden switch" because no one knew it played this role before.
The discovery also flips a long-held assumption about how cells work. Scientists believed that a process called RNA editing generally weakened the alarm molecules, making them less likely to trigger immune responses. Instead, the team found that certain RNA editing events can actually strengthen these signals — and DDX6 blocks those helpful edits from happening.
"What surprised us most was that the biology did not behave the way we expected," said Dr. Larry Ng, the study's first author. "For years, researchers believed RNA editing generally weakened these immune-triggering RNA molecules. Instead, we found that certain RNA editing events can actually strengthen them."
In laboratory experiments, the researchers found that removing DDX6 allowed cancer cells to become visible again. Immune signaling was restored, and tumors grew more slowly. The team, led by Associate Professor Polly Chen, is now searching for molecules that can block DDX6 — drugs that could essentially remove the cloak and let the immune system do its job.
The findings, published in the journal Science Immunology, point to DDX6 as a promising new target for cancer immunotherapy — treatments that help the body's own defenses fight cancer. The researchers plan to study additional proteins involved in this pathway and how they contribute to cancer's ability to hide.
The work changes not only how scientists think about cancer but also how they understand the relationship between RNA editing and the immune system more broadly. For patients, this research offers a new avenue worth watching.