WEDNESDAY, Jan. 3 (HealthDay News) -- A cluster of five genes may predict a better outcome after treatment for patients with lung cancer, Taiwanese researchers report.

The study highlights the increasingly important role of genetics in lung cancer care, one U.S. expert said.

"This is one of several studies over the last few years looking at genes to predict that if a tumor is removed surgically, who does well and who should get more aggressive therapy," said Dr. Roy S. Herbst, chief of the section of thoracic medical oncology at the M.D. Anderson Cancer Center in Houston, and co-author of an editorial accompanying the report in the Jan. 4 New England Journal of Medicine.

"Now, we have to move toward personalizing therapy," Herbst said.

In the study, a team of cancer specialists at National Taiwan University, Taipei, studied the expression of a variety of genes in tissue samples from 125 people who had surgery for lung cancer. They identified 16 genes associated with better survival.

They then narrowed their search to five genes from that array. This "five-gene signature was an independent predictor of relapse-free and overall survival," the researchers reported.

"If we are truly going to make inroads in lung cancer, we have to look at genes," Herbst said. "At M.D. Anderson, we are very focused on genes to personalize therapy for persons with lung cancer."

But the Houston program is in its early stages, Herbst said. If an early treatment fails in a patient, a genetic analysis is made of a tissue sample to help determine what to do next. "The problem is, we don't know which genes are the best," Herbst said. "We are learning as we go along."

A similar kind of genetic analysis is being used in the treatment of lung cancer patients at Memorial Sloan-Kettering Cancer Center in New York, said Dr. Vincent A. Miller, an associate attending physician in the center's thoracic oncology service. The new gene analysis is based on the identification of a mutation associated with lung cancer, he said.

"We take patients and either treat or don't treat with specific drugs depending on whether they have a specific mutation," Miller said.

The Taiwanese study is "very interesting," but it needs verification by "larger studies and studies by other groups," he said. One potential problem: Different genes might be more or less important for different ethnicities, Miller said.

"Lung cancer in the Far East may be different than lung cancer in the United States," he said. For example, Miller's studies have shown that most people who develop lung cancer in South Korea are not smokers, whereas smoking is by far the leading cause of lung cancer in the United States.

"It may be different genetics or different environmental factors -- cooking oil, for example," Miller said.

But the genetics of lung cancer is not infinitely complicated, he said. "It isn't different for every individual," Miller said. "It might be 10 or 20 different genes in all."

More information

Find out more about the genetics of lung cancer at the U.S. National Cancer Institute.