A gene which encourages cancer to move around the body has been discovered by the University of East Anglia.
Experiments on tissue cultures, published in Oncogene, suggest that blocking it would prevent cancers spreading.
The researchers hope their work will lead to a new generation of cancer drugs within the decade.
Cancer Research UK said the study improved understanding of the disease, but was still at the laboratory stage.
There are treatments for primary cancers, but tumours have the potential to spread.
Cells can break off and travel around the body, through the bloodstream or lymph fluid, and start a new or secondary tumour where they land, a process known as metastasis.
Breast cancers are known to spread to lymph nodes, the bones and the lungs.
These secondary tumours are notoriously difficult to treat.
The rogue gene
The team at the University of East Anglia has found a gene which helps the cancer spread.
The gene, WWP2, leads to the breakdown of an inhibitor that normally keeps cells in check.
The researchers showed, in tissue cultures, that without the inhibitor, Smad7, cancer progressed very quickly and spread.
Blocking the gene prevented that spread.
Dr Andrew Chantry, who led the study, said: "I think we're really onto something important if we can put a wall around a cancer and lock it in place.”
"The discovery could lead to the development of a new generation of drugs within the decade that could be used to stop the aggressive spread of most forms of the disease."
The team are now recruiting chemists to help them design a drug which could interrupt the gene's activity.
Dr Kat Arney, science information manager at Cancer Research UK, said: "Over recent decades researchers all over the world have discovered genes that drive the growth and spread of cancer, and this research adds one more to this ever-growing list.
"But, while these new results aid our understanding of the complexities of cancer and could point towards potential leads for future anti-cancer drugs, the work is still at the laboratory stage."