Biologists in Britain have discovered a link between the human body clock and the risk of breast cancer, the University of Manchester announced Tuesday.
Chinese-born Dr. Qing-Jun Meng and Professor Charles Streuli have discovered that breast tissues have 24-hour body clocks, and that several hundred genes are regulated in a daily cycle.
They say their discovery may offer the first evidence of a link between breast biology, including breast cancer risks, and the human body clock.
They found that ageing of breast tissue has a central role in controlling these clocks.
A spokesman at the university explained: "Breast tissues get stiffer as they get older which, the authors found, causes the clocks to get weaker."
Higher mammographic density, or breast tissue stiffness, is a known risk factor for breast cancer, according to the spokesman, but the way that stiffness contributes to cancer is not known.
Research funded by Britain's Medical Research Council and Wellcome enabled the Manchester biologists to discover that the amplitude (strength) of clocks within breast cells is dependent on the biological stiffness of the tissue.
They also found that body clocks are needed for the production breast stem cells.
The weakening of clocks in ageing may therefore reduce normal stem cells, and it may help cause the tissue to become cancerous.
Their study was published Tuesday in the journal Nature Communications.
Dr. Meng said: "We have discovered that tissue stiffness contributes to the age-dependent dysregulation of both clocks and stem cell function in the breast tissue."
"There is now a widening interest in the importance of stem cells for the formation of breast cancers - so our findings in relation to that are of much interest," explained Meng.
Prof Streuli said: "A lot of epidemiological work links both breast tissue density and body clock disruption to the risk of getting breast cancer. And now for the first time we've identified a biological link."
Meng is currently Senior Research Fellow in the Faculty of Biology, Medicine and Health, at the University of Manchester. He obtained his first degree in medicine in China in 1996, as well as an MSc and doctorate, also in China.
In 2003, Meng began his post-doctoral training at the University of Manchester, eventually starting his own research group to continue his work into the roles of the cartilage circadian clocks in health and disease of the joint tissue.
Meng's journey into the world of body clocks started as he worked in China as a flight surgeon in the aviation industry.
He says the work as a flight surgeon and his ongoing research into how changes in the body's circadian rhythm during ageing cause disease are no so different.
"It sounds like discipline hopping, but some of the lectures I gave to pilots were about body clocks and jet lag. That was when I first got interested in the field," he said.