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 tumours.

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.

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 one million people worldwide each year, including more than 150,000 in the United States. 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.