Public Health

Cancer’s genetic fingerprints may lurk in people’s blood long before they find out about the disease.

It’s possible to spot tumor DNA more than three years before a person is diagnosed with cancer, researchers report May 22 in Cancer Discovery. “We were shocked that we could find DNA,” says Yuxuan Wang, an oncologist and cancer researcher at Johns Hopkins University School of Medicine.

The findings suggest that hunting for these telltale traces using highly sensitive and accurate technology could be a powerful tool in early cancer screening efforts. It could one day help doctors detect cancers before any other signs or symptoms of the disease appear, she says. Even a diagnosis that’s a few months earlier than usual might mean more treatment options for patients. And a yearslong head start could be lifesaving. “It would dramatically change outcomes for our patients,” Wang says.