BOSTON (AP) - Scientists in Boston have announced they're
teaming up with Johnson & Johnson to bring a new cancer test to
market.

The blood test is so sensitive it can spot a single cancer cell
among a billion healthy ones. Many doctors think stray cancer cells
in the blood mean that a tumor has spread or is likely to spread.

Four big cancer centers will start studies this year using the
experimental test, which could potentially transform care for many
types of cancer.

Initially, doctors want to use the test to try to predict what
treatments would be best for each patient's tumor and find out
quickly if they are working.

One of the inventors of the test says it's "like a liquid
biopsy." Dr. Daniel Haber of Massachusetts General says it can
avoid the painful sampling of tissue. And he says it could be a
better way of monitoring patients than periodic imaging scans.