THE BIOMEDICAL TESTING REVOLUTION

“CANCER SIGNAL NOT detected.” That was the happy finding of my Galleri multicancer early detection (MCED) blood test from the Silicon Valley biotech company GRAIL. The Galleri test presages an emerging wave of new precision biomedical tests produced by a panoply of biotech startups.

- RONALD BAILEY

GRAIL’s MCED test analyzes DNA shed by both normal and cancerous cells into a person’s bloodstream, looking for telltale epigenetic changes that affect the way genes operate. Specific changes are associated with the presence of cancer cells.

Published research indicates that the test can detect a shared signal across more than 50 types of cancer. They include pancreatic, liver, and kidney cancers, which are difficult to diagnose early. The Galleri test not only detects a cancer signal but also provides two predictions of the cancer signal’s origin to inform further diagnostic evaluation. 

MCED screening is a potentially significant advance because there are currently only five recommended cancer screening tests: for breast, colorectal, lung, cervical, and prostate cancers. Around 70 percent of new cancer diagnoses and deaths are due to cancers for which there are no recommended screening tests.