A protein produced by some tumors has the potential to promote other cancers in body, a new study has found.
The study led by Whitehead Institute's Robert Weinberg found that certain cancers produce a protein, called osteopontin, which triggers growth of distant or dormant cancer cells in body.
Researchers revealed that most patients who die from cancer do not succumb to the initial cancer, called a primary tumour, but rather from the disease's spread to other parts of the body.
They believe that the novel finding would help doctors understand and prevent the progression of cancer in body.
"For some reason the cells are just sitting there, dormant until something stimulates their growth," Nature quoted Sandra McAllister, co researcher, at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, as saying.
"We didn't really know what those events are that activate disseminated metastatic cells," she added.
For the study, researchers co-implanted two kinds of cancer cells in mice, the first, which they termed as 'instigator' tumour, was made of fast-growing breast-cancer cells cultured in the lab.
They also injected other cancer cells, called 'responder' cells, which were known to grow slowly and metastasize only rarely.
The findings revealed that presence of the instigator tumour speed up development of the responder, which then generated up to nine times as many metastatic tumours as when the instigator was absent.
They found similar results when they repeated the experiment using colon cancer cells collected from cancer patients as the responder tumours.
The team discovered that osteopontin protein played a crucial role in the instigator effect.
The rising levels of this protein have been linked to elevated risk of death from several cancers, including breast and prostate cancers.
On blocking the osteopontin production in the cancer cells, the results showed that the instigator tumour continued to grow and thrive, but it no longer stimulated responder cells.
Ann Chambers, a cancer researcher at the London Health Sciences Centre in Ontario, Canada, said that the study has come identified an important new mechanism by which cancer spreads. However, testing it in humans is a challenging next step.
The study is published in Cell 1.