Johnson & Johnson Boosting Blood Cancer Test (JNJ)

Johnson & Johnson

is up 37 cents in pre-market trading to $62.31 on news that it's joining a blood test that potentially allows doctor's to spot a single cancer cell lurking among a billion healthy ones. The test was invented by

Doctors want to use the test to to predict what treatments would be best for the patient's tumor and find out quickly if it's working. "This is like a liquid biopsy" said Dr. Daniel Haber, chief of Massachusetts General Hospital's cancer center. Haber was one of the test's inventors. "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 Cancer Center in New York. Sloan-Kettering is one of the sites that will study it this year. "If you could find out quickly, 'this drug is working, stay on it,' or 'this drug is not working, try something else,' that would be huge," Haber said.