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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.
A study of aberrations in the genetic code of lung adenocarcinoma - the most common form of lung
cancer - found 57 changes frequently associated with the tumours.
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 is online in the journal Nature.
The most common change uncovered in this study is involved in as many as 12 per cent of lung cancer tumours. "This is a cancer gene that is special for lung cells," Dr Meyerson said.
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 Dr 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 one million people worldwide each year.
The findings are the first phase of the Tumour 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 centres. Researchers looked for common genetic changes in more than 500 tumour specimens from lung cancer patients. The study is based on the understanding that most human cancers stem from changes in DNA 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," Dr Meyerson said, referring to the NKX2-1 discovery.
Far less common was the discovery of extra copies of the HER2 gene, a hallmark of an aggressive type of breast cancer, which can be treated with the drug Herceptin, made by Genentech.
"It is not a new discovery but it points out that lung cancer could also be treated with Herceptin," Dr Meyerson said.
The next phase of research involves sequencing the genome for mutations specific to lung cancer.
The Tumour 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.
- Reuters