VOA常速英语:Researchers Identify Defective Genes Responsible for Lung Cancer

Scientists say they have identified more than two dozen genes that are frequently mutated in people with the most common form of lung cancer. The researchers say the findings open the possibility of developing individualized therapies to fight the disease. VOA's Jessica Berman reports.

Genetics researchers at three U.S. institutions have identified 26 genes that are frequently mutated in people with the most common form of lung cancer, adenocarcinoma.

Lung cancer is the number one cancer killer worldwide, accounting for one million deaths each year. About 90 percent of those stricken with the disease are smokers and former smokers, and about 10 percent non-smokers.

Only 15 percent of people diagnosed with the deadly disease are alive five years later.

In a study published this week in the journal Nature, the researchers describe using the latest genetic sequencing technology to sort through 625 genes taken from the tumors of 188 lung cancer patients.

The investigators then compared the tumor changes to the DNA in healthy tissue from the same patients.

In a teleconference with reporters, senior study author Matthew Meyerson of the Broad Institute at the Massachusetts Institute of Technology in Boston said the cancer genes, known as somatic cell mutations, are not inherited and occur nowhere else in the body.

He said, "Somatic mutations are important because the mutated genes can be targets for anti-cancer therapy. The reason is that the cancer gene is now different from the normal gene and so some drugs can now specifically kill cells with the mutated cancer gene."

Investigators examined which faulty genes activate the cascade of biological events that lead to the development of adenocarcinoma.

Senior-co-author Richard Wilson of Washington University School of Medicine in Saint Louis, Missouri said the development could, in time, lead to targeted therapies for lung-cancer patients.  

"We should be able to develop much more effective chemo [chemotherapy] drugs, including drugs that also provide for a much more improved quality of life for the patients," he said.

The researchers found that some adenocarcinoma genes have been implicated in a number of other cancers, including lymphoma, leukemia and colon cancer.

Investigators said it is possible that some drugs that show promise against one type of tumor might work against adenocarcinoma.

The work is part of the Tumor Sequencing Project, funded by the National Human Genome Research Institute, to assemble a genome-wide catalog of all mutations involved in the lung disease.