Cancer cells can "poison" neighbouring cells they come into contact with, causing them to become cancerous, a study has found.
Scientists in the US studied the effect using a three-dimensional cell-culturing system that mimics conditions in the body.
They found that cancer cells produce an enzyme that splits a molecule from normal "epithelial" cells that line body cavities and organs.
The freed molecule, called soluble E-cadherin, or sE-cad, plays a key role in turning good cells bad.
"The serum of adult cancer patients contains high levels of sE-cad," said lead researcher Dr Pratima Patil, from the University of Delaware.
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"Our finding documents that tumour cells modify normal epithelial cells, disrupting their cellular architecture, and use them as accomplices to generate sE-cad, which is known to facilitate tumour progression."
The findings, published in the Journal of Cell Science, open up new areas of cancer research, said the team.
They also raise the possibility of slowing cancer progression by reducing sE-cad levels in cancer patients.
Professor Ayyappan Rajasekaran, a materials scientist at the University of Delaware, said: "Like bacteria and viruses, cancer cells have the potential to infect normal cells and promote cancer progression."
