Scientists discover how cancer spreads

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Scientists discover how cancer spreads

Disease sends bone marrow cells to prepare new tumor sites, study finds

 

 

LONDON - Scientists have discovered how cancer spreads from a primary

site to other places in the body in a finding that could open doors

for new ways of treating and preventing advanced disease.

 

Instead of a cell just breaking off from a tumor and traveling through

the bloodstream to another organ where it forms a secondary tumour, or

metastasis, researchers in the United States have shown that the

cancer sends out envoys to prepare the new site.

 

Intercepting those envoys, or blocking their action with drugs, might

help to prevent the spread of cancer or to treat it in patients in

which it has already occurred.

 

" We are basically looking at all the earlier steps that are involved

in metastasis that we weren't previously aware of. It is complex but

we are opening the door to all these things that occur before the

tumor cell implants itself, " said Professor David Lyden, of Cornell

University in New York.

 

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

interview.

 

Landing site for cancer cells

Cancer's ability to colonize other organs is what makes the disease so

deadly. Once the cancer has spread beyond its original site it is much

more difficult to treat.

 

In research reported in the journal Nature, Lyden and his colleagues

describe what happens before the arrival of the cancerous cells at the

new site.

 

" The authors show that tumor cells can mobilize normal bone marrow

cells, causing them to migrate to particular regions and change the

local environment so as to attract and support a developing

metastasis, " Patricia Steeg, of the National Cancer Institute in

Bethesda, Maryland, said in a commentary.

 

Cells at the site of the metastasis multiply and produce a protein

called fibronectin, which acts like a glue to attract and trap the

bone marrow cells to create a landing pad or nest for the cancer cells.

 

" These nests provide attachment factors for the tumor cells to implant

and nurture them. It causes them not only to bind but to proliferate.

Once that all takes place we have a fully formed metastatic site or

secondary tumor, " said Lyden.

 

" This is the first time anyone has discovered what we call the

pre-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 tumor

determine the site of the secondary site.

 

Lyden said measuring the number of special bone marrow cells

circulating in the body could help to determine whether a cancer is

likely to spread.

 

" This opens up the door to new concepts of how metastasis is taking

place. If we can understand all these multiple processes we can

develop new drugs that block each step. That way we have a much better

future than just trying to treat the tumor cell, which is almost like

a last step in this process, " he added.