Genomic profiling of lung tumor might help in effective treatment

Washington, Sept 30: A new study has revealed that by determining the genetic profile of a particular lung tumor doctors may be able to decide which chemotherapy treatment to try first.

The study led by researchers from the Duke University Comprehensive Cancer Center and the Duke Institute for Genome Sciences & Policy (IGSP) found distinct differences in the susceptibility different tumors have to the widely used chemotherapy drugs.

“We were able to predict which tumors would be most likely to respond to standard first-line therapy and which would respond better to what has traditionally been a second-line therapy, based on gene expression profiling,” said David Hsu, M.D., Ph.D. an oncologist at Duke and lead author of the study.

“This represents a big step in the move toward individualized medicine. This could also make a huge difference in the treatment of patients with late-stage lung cancer, as most of these patients gain the most benefit from their initial treatment strategy,” he said.

As a part of the study, researchers looked at the sensitivity of multiple cancerous cell lines to cisplatin, which is the most commonly used agent in the treatment of lung cancer.

After the determination of the cell lines, which were responsive to cisplatin, they looked at the RNA of these tumors and generated a genomic signature, a pattern of gene expression particular to each individual sample.

They drew conclusions as to which genes were turned on and which were turned off in these samples, and subsequently created a genomic map for cisplatin sensitivity.

The genomic map was then applied to 91 non-small cell lung cancer (NSCLC) tumor samples in order to determine which tumors were most likely to be responsive to cisplatin.

“We found that tumors known to be sensitive to cisplatin expressed certain genes that were not expressed in tumors that were resistant to cisplatin. The reverse was true, as well; genes that were not expressed in tumors resistant to cisplatin seemed to be turned on in tumors that were sensitive to it,” senior author Anil Potti, M.D., an oncologist at Duke and a researcher in the IGSP said.

Potti said that the important second part of this project was to come up with a therapy option for the tumors that weren’t sensitive.

“It’s one thing for a doctor to tell a patient that he won’t respond to cisplatin, but we have to know what to do when he asks ‘what do you have for me" Potti said.

The researchers then examined several common second-line therapies, such as a drug called pemetrexed, which used a different mechanism of action to attack NSCLC tumors.

“We found the strongest inverse correlation between tumors that were sensitive to cisplatin and those that were sensitive to pemetrexed,” Potti said

“This suggests that some patients who are not likely to respond to cisplatin should perhaps be treated with pemetrexed first,” he added.

The study will be issued in the Journal of Clinical Oncology. (With inputs from ANI)