Genetic testing is meant to bring clarity about inherited cancer risk. Most results are straightforward, clearly marked as harmful or harmless. But sometimes, a test report falls into a grey area. A Variant of Uncertain Significance (VUS) means a genetic change has been found, but doctors don’t yet know whether it affects health or cancer risk.

What does VUS mean? 

A Variant of Uncertain Significance (VUS) is a genetic change found during testing that doctors don’t fully understand yet. It means the change hasn’t been clearly linked to disease, but it also can’t be ruled out as harmless. This happens because genetics is still evolving, and not every DNA variation has been studied in detail. Over time, as more research becomes available, a VUS may later be reclassified as benign or pathogenic.

Why are VUS results hard to understand?

VUS results are confusing because science doesn’t have all the answers yet. Many of these genetic changes are very rare, meaning only a few people in the world have them. That makes it hard for researchers to study them properly. Our understanding of genes is also still growing. Some genetic changes clearly stop a gene from working, but a VUS may only change it slightly. These small changes are harder to judge, which is why doctors can’t say for sure what they mean.

What does a VUS mean for patients and families?

When someone receives a VUS result, it means a change was found in a gene linked to conditions like cancer—but it doesn’t mean they will get sick. A VUS does not automatically increase disease risk. In fact, many VUS results later turn out to be harmless. It simply means there isn’t enough information yet to label the change as good or bad.

What to do after a VUS result?

After getting a VUS result, meeting a genetic counsellor is important. They explain what the result means and look at the person’s health and family history. If there is a strong family history of cancer, doctors may watch more closely. Patients should continue regular check-ups based on their personal risk. Over time, labs may review the results again and update them when new research becomes available.

Hope beyond the uncertainty

Although a VUS can feel worrying, research is moving forward. Scientists around the world share data in large genetic databases to better understand these rare changes. As more people are studied, many VUS results are reclassified. What is unclear today may become clear in the future, helping doctors turn uncertainty into better care and clearer health plans.