Study points to way of stopping lung cancer spread

By Will Dunham

WASHINGTON (Reuters) - Lung cancer cells produce a compound that helps the tumor spread to other parts of the body, a finding that could lead to a new way to prevent this dangerous development, researchers reported on Wednesday.

They said a protein called versican hijacks elements of the immune system, generating inflammation that can spur the growth and spread of lung cancer.

Michael Karin of the University of California, San Diego, and colleagues made the findings in experiments with mice, but said the protein is found in low levels in some normal human lung cells and other tissues.

Versican is made in large amounts by lung cancer cells, especially in aggressive tumors, they reported in the journal Nature.

Cancer becomes far more dangerous and hard to treat when it spreads from the original tumor site -- the lungs in this study -- to other parts of the body in a process called metastasis.

The researchers said their findings could lead to new treatments to limit the metastasis of lung cancer, perhaps by blocking the cancer cells from secreting the protein.

Versican was known to be involved in the development of embryos, and known to be active in some tumors, although its role was not clearly understood.

The study showed that versican causes the production of immune system proteins called cytokines, generating inflammation that fuels the growth and spread of the cancer.

"Our research showed that versican which (is) produced by cancer cells induced inflammatory response and this whole process enhances metastasis. This simply says that blocking versican or blocking the inflammatory response can reduce the metastatic incidence. However, it is not that easy," Sunhwa Kim, one of the researchers, said by e-mail.

The immune system's complexity is one hurdle, Kim said.

Kim, who previously worked in Karin's lab and now works for Johnson & Johnson, called the findings a good starting point for human studies focusing on this protein.

Worldwide, lung cancer is the leading cause of cancer death in men and the second leading cause of cancer death in women, with about 975,000 men and 376,000 women dying annually, according to the American Cancer Society. About 1.5 million new cases of lung cancer occur per year.

(Editing by Maggie Fox and Xavier Briand)