Scientists discover how cancer spreads

[Guest guest]

http://www.msnbc.msn.com/id/10366968/

 

Scientists discover how cancer spreadsDisease sends bone marrow cells to prepare new tumor sites, study finds

 

LONDON - Scientists have discovered how cancer spreads from a primarysite to other places in the body in a finding that could open doorsfor new ways of treating and preventing advanced disease.

 

Instead of a cell just breaking off from a tumor and traveling throughthe bloodstream to another organ where it forms a secondary tumour, ormetastasis, researchers in the United States have shown that thecancer sends out envoys to prepare the new site.

 

Intercepting those envoys, or blocking their action with drugs, mighthelp to prevent the spread of cancer or to treat it in patients inwhich it has already occurred.

 

"We are basically looking at all the earlier steps that are involvedin metastasis that we weren't previously aware of. It is complex butwe are opening the door to all these things that occur before thetumor cell implants itself," said Professor David Lyden, of CornellUniversity in New York.

 

"It is a map to where the metastasis will occur," he added in aninterview.

 

Landing site for cancer cellsCancer's ability to colonize other organs is what makes the disease sodeadly. Once the cancer has spread beyond its original site it is muchmore difficult to treat.

 

In research reported in the journal Nature, Lyden and his colleaguesdescribe what happens before the arrival of the cancerous cells at thenew site.

 

"The authors show that tumor cells can mobilize normal bone marrowcells, causing them to migrate to particular regions and change thelocal environment so as to attract and support a developingmetastasis," Patricia Steeg, of the National Cancer Institute inBethesda, Maryland, said in a commentary.

 

Cells at the site of the metastasis multiply and produce a proteincalled fibronectin, which acts like a glue to attract and trap thebone marrow cells to create a landing pad or nest for the cancer cells.

 

"These nests provide attachment factors for the tumor cells to implantand nurture them. It causes them not only to bind but to proliferate.Once that all takes place we have a fully formed metastatic site orsecondary tumor," said Lyden.

 

"This is the first time anyone has discovered what we call thepre-metastatic niche."

 

Without the landing pad, the cancerous cell could not colonize the organ.

 

In animal and laboratory studies, the scientists looked at how breast,lung and oesophageal cancer spread. The envoys from the tumordetermine the site of the secondary site.

 

Lyden said measuring the number of special bone marrow cellscirculating in the body could help to determine whether a cancer islikely to spread.

 

"This opens up the door to new concepts of how metastasis is takingplace. If we can understand all these multiple processes we candevelop new drugs that block each step. That way we have a much betterfuture than just trying to treat the tumor cell, which is almost likea last step in this process," he added.