Washington, Feb 1 (IANS): A new study shows that a combination of drugs can be used in targeted therapy against a common type of lung cancer.

Lung adenocarcinomas, the most common genetic subtype of lung cancer which has long defied treatment with targeted therapies, has had its growth halted by a combination of two already-in-use drugs in laboratory and animal studies, setting the stage for clinical trials of the drugs on patients, researchers at Dana-Farber Cancer Institute in Boston, Massachusetts and other scientists report in a new study.

The study, published in the journal Cancer Discovery, describes a new tack in the treatment of lung adenocarcinomas which account for about 40 percent of all lung cancers that carry mutations in the gene KRAS.

While most efforts to target KRAS directly with drugs have not proved successful, the authors of the current study took a more circuitous approach, targeting KRAS's accomplices, the genes that carry out its instructions rather than KRAS itself, reports Science Daily.

"About 30 percent of lung adenocarcinomas have mutations in KRAS which amount to nearly 30,000 of all patients diagnosed with lung cancer each year in the United States," says the study's senior author, David Barbie, MD, of the Lowe Centre for Thoracic Oncology at Dana-Farber and the Broad Institute of Harvard and Massachusetts Institute of Technology.

"That represents the single biggest subset of lung cancer patients, if grouped by the mutations within their tumour cells. Unfortunately, there has not been a reliable way of striking at the genetic mechanism that causes these cells to proliferate."

Mutations in KRAS cause cancer cells to grow and divide in a wildly disordered way. The lack of drugs able to block KRAS safely has led investigators to look for ways of stifling its effects "downstream" -- by interfering with the signals it sends to other genes.

"The next step will be to take these results to the clinic where the combination can be tested on lung cancer patients," says Wong. "We're in the process of developing a clinical trial. Because KRAS mutations are also common in colon and pancreatic cancer, we're hopeful that trials will be organised for these patients as well."