Breast cancer spreads at night new research shows

By Mark Waghorn via SWNS

Breast cancer spreads at night, new research shows, which could help target the spread of the disease.

Tumors are most active while women sleep - making daytime therapy less effective.

Researchers found they are fueled by the hormone melatonin - produced in response to darkness.

The findings also have implications for when breast biopsies are carried out.

Project leader Professor Nicola Aceto explained: "When the affected person is asleep, the tumor awakens."

A study of 30 patients showed more cancerous cells were generated at night.

It also applied to mice. The disease was most aggressive during the day - as they are nocturnal animals.

First author Dr. Zoi Diamantopoulou said: "Our research shows the escape of circulating cancer cells from the original tumor is controlled by hormones such as melatonin - which determine our rhythms of day and night."

Melatonin is produced by the pineal gland - a pea-sized organ at the base of the brain. It dictates our sleep patterns.

The phenomenon may influence the examinations of patients by oncologists.

Results could be affected depending on the time in which tumor or blood samples are taken.

It was a serendipitous discovery along these lines that put the Zurich-based scientists on the right track.

Prof Aceto said: "Some of my colleagues work early in the morning or late in the evening - sometimes they'll also analyse blood at unusual hours."

The team from the Swiss Federal Institute of Technology noticed samples taken at different times of the day had very different levels of circulating cancer cells.

Another clue was the surprisingly high number of cancer cells found per unit of blood in mice compared to humans.

The reason was the lab rodents sleep during the day - which is when researchers collect most samples.

To date, little attention has been paid to the question of when tumors spread - or metastasize. It was previously assumed they release such cells continuously.

But the study in Nature turns the idea on its head - showing they mainly arise during the sleep phase of affected individuals.

Prof Aceto said: "In our view, these findings may indicate the need for healthcare professionals to systematically record the time at which they perform biopsies. It may help to make the data truly comparable."

Each year in the United States, about 264,000 cases of breast cancer are diagnosed in women and about 2,400 in men. About 42,000 women and 500 men in the U.S. die each year from breast cancer.

Globally, there are around 2.3 million new cases of breast cancer and almost 700,000 deaths every year.

The time medications should be taken to improve their effectiveness is an increasing area of interest.

It could revolutionize patient care. Body clock-related changes have been identified in the actions of more than 100 drugs.