New blood test can spot single cancer cell

BOSTON - A blood test so sensitive that it can spot a single cancer cell lurking among a billion healthy ones is moving a step closer to your doctor's office.

Boston scientists who invented the test and health care giant Johnson & Johnson will announce Monday that they are joining forces to bring it to market. Four big cancer centers, including the Memorial Sloan-Kettering Cancer Center in Manhattan, also will start studies using the experimental test this year.

Stray cancer cells in the blood mean that a tumor has spread or is likely to, many doctors believe. Initially, doctors want to use the new test to try to predict what treatments would be best for each patient's tumor and find out quickly if they are working.

"This is like a liquid biopsy" that avoids painful tissue sampling and may give a better way to monitor patients than periodic imaging scans, said Dr. Daniel Haber, chief of Massachusetts General Hospital's cancer center and one of the test's inventors.

Ultimately, the test may offer a way to screen for cancer besides the mammograms, colonoscopies and other less-than-ideal methods used now. "There's a lot of potential here, and that's why there's a lot of excitement," said Dr. Mark Kris, lung cancer chief at Memorial Sloan-Kettering who had no role in developing the test.

The only test on the market now to find tumor cells in blood - CellSearch, made by J&J's Veridex unit - gives a cell count but doesn't capture whole cells that doctors can analyze to choose treatments.

The test uses a lab slide-like microchip covered with 78,000 tiny, specially treated posts, like bristles on a hairbrush. The cancer cells stick, and stains make them glow so researchers can study them. No price goal has been set, a J&J official said, but the current CellSearch test costs several hundred dollars.