From: By Julie Steenhuysen
Published November 4, 2007 06:53 PM

Sweep of lung cancer genome reveals new gene

CHICAGO (Reuters) - An effort to map the genetic landscape of lung cancer has turned up a host of new genes, including one that controls the growth of cells essential for lung function, an international team of researchers said on Sunday.

This study of aberrations in the genetic code of lung adenocarcinoma -- the most common form of lung cancer -- found 57 changes frequently associated with the tumors.

Only about a third of the changes are linked with the 15 genes already known to play a role in lung cancer.

"It is important to find these alterations in the cancer genome because it can tell us about what causes cancer and how to treat it," said Dr. Matthew Meyerson of the Broad Institute of the Massachusetts Institute of Technology and Harvard University, whose study appears online in the journal Nature.

The most common change uncovered in this systematic study is involved in as many as 12 percent of lung cancer tumors.

"This is a cancer gene that is special for lung cells," Meyerson said in a telephone interview.

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The gene, known as the NKX2-1, controls the activity of alveoli, which are tiny air sacs in the lungs that facilitate the exchange of oxygen and carbon dioxide.

"If you have mice that lack this gene, they don't make alveoli and they can't breathe. They die when they are born," said Meyerson, who is also an associate professor at the Dana-Farber Cancer Institute in Boston.

The study suggests this gene can mutate into one that promotes the growth of lung cancer, which kills more than 1 million people worldwide each year, including more than 150,000 in the United States.

FIRST STEPS

The findings are the first phase of the Tumor Sequencing Project, which also involved genome researchers from Baylor College of Medicine in Houston and Washington University in St. Louis, as well as several cancer research centers.

Researchers looked for common genetic changes in more than 500 tumor specimens from lung cancer patients. The study is based on the understanding that most human cancers stem from changes in DNA that occur over time.

The researchers were looking for extra or missing pieces of DNA.

"It turns out that the most common change is a lung-cancer specific gene," he said, referring to the NKX2-1 discovery.

Far less common was the discovery of extra copies of the HER2 gene, which is a hallmark of an aggressive type of breast cancer. It can be treated with the targeted drug Herceptin, made by Genentech.

"It is not a new discovery but it points out that lung cancer could also be treated with Herceptin," he said.

There also are extra copies of the gene that makes telomerase, an enzyme associated with aging and cancer.

The next phase of this research involves sequencing the genome for mutations specific to lung cancer. Meyerson said that work has been done but the analysis is still under way. "There's more good stuff coming and lots of it," he said.

Ultimately, the Tumor Sequencing Project will lay the foundation for more cancer genome efforts, including The Cancer Genome Atlas, a project of the National Human Genome Research Institute and the National Cancer Institute, which aims to sequence a wide range of human cancers.

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