New therapies to stop the deadly progression of breast cancer in its tracks could stem from a new study into the disease, researchers believe.
Scientists at Edinburgh University have discovered a "trigger" that allows breast cancer cells to spread to the lungs.
They found that blocking those signals in mice with breast cancer "greatly reduces" the number of secondary tumours found in the lungs.
The researchers hope their findings may one day translate into new treatments to stop the progression of breast cancer within the human body.
Most deaths from breast cancer are said to be caused by the tumour spreading to other parts of the body, with the lungs often among the first organs affected.
Researchers at the university's MRC Centre for Reproductive Health investigated the role immune cells called macrophages play in helping cells from the original tumour to spread.
Previous research has shown breast cancer cells need the support of macrophages to invade the lungs and set up secondary tumours. The team's latest research found macrophages need signalling molecules called chemokines to communicate with breast cancer cells.
But when scientists blocked the signals in mice, the number of secondary tumours in the lungs was reduced by two-thirds.
"Our findings open the door to the development of treatments that may stop the deadly progression of breast cancer," said centre director Prof Jeffrey Pollard.