A new method of combating breast cancer has been discovered by scientists after they pinpointed a key driver for its growth and spread.
Researchers found a protein called lysyl oxidase, or Lox, allowed breast cancer cells to latch on to growth receptors - helping them grow more rapidly.
This also allowed the deadly cells to advance through the body, their study found.
The findings, hailed as a "game changer", led scientists to develop a new prototype drug which could pave the way for the next generation of treatment for the disease.
When tested on mice, the medicine halted the protein's capacity to help cancer cells, slowing both the growth of tumours and the rate at which cells multiplied, scientists said.
The work, carried out by a team from the University of Manchester and Institute of Cancer Research, will now lead to the drug being refined and presented for clinical trials on patients.
Caroline Springer, joint senior author of the study published in the journal Nature Communications, said: "We knew that Lox had a role in cancer's spread round the body, but to discover how it also appears to drive the growth of breast cancer cells is a real game changer.
"It means that drugs that disrupt Lox's ability to promote growth signals might be able to slow or block cancer progression in patients - as we saw in mice."
Lox has also been shown to play a role in lung, bowel, prostate and pancreatic cancer, meaning the new treatment could be rolled out to a larger number of those afflicted by the illness.
Initially, the experts found they could mitigate the development of breast cancer in mice by genetically removing the Lox gene, allowing them to live more than 50 days.
By depleting the protein, it reduced the surface levels of a receptor on the cancer cell which is often blamed for facilitating its growth - the epidermal growth factor receptor.
They used the findings to design and validate an inhibitor drug which slowed the tumour growth and spread with no side effects, the study said.
It is the first time Lox has been identified as having a controlling influence on tumour growth, researchers said.
Dr Justine Alford, senior science information officer at Cancer Research UK, said: "This research in mice is exciting because it not only reveals new details of how breast cancer grows and spreads, but it could lead to a completely new way to stop these processes in patients if proven in people.
"This could help improve outcomes for patients, since cancer that has spread is harder to treat.
"LOX is also thought to play a role in a number of other cancers, so this research could also have applications beyond breast cancer."