An experimental blood test that can spot a single cancer cell among a billion healthy ones has taken a step closer to being brought to market.

The Boston scientists who invented the test and health care giant Johnson & Johnson will announce that they are joining forces to bring it to market. Four big cancer centres also will start studies using the experimental test this year.

Stray cancer cells in the blood mean that a tumour has spread or is likely to, many doctors believe. A test that can capture such cells has the potential to transform care for many types of cancer, especially in the breast, prostate, colon and lung.

Initially, doctors want to use the test to try to predict what treatments would be best for each patient’s tumour 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 centre 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 Cancer Centre in New York. He had no role in developing the test, but Sloan-Kettering is one of the sites that will study it this year.

Studies of the chip have been published in the journals Nature, the New England Journal of Medicine and Science Translational Medicine. It is the most promising of several dozen that companies and universities are rushing to develop to capture circulating tumour cells, said Bob McCormack, technology chief for Veridex.