East Asians, Europeans: Genomic Features of Lung Adenocarcinoma Differ

East Asians, Europeans: Genomic Features of Lung Adenocarcinoma Differ

Last Updated on February 5, 2020 by Joseph Gut – thasso

February 05, 2020 – Lung adenocarcinoma is a common cancer and leads to more than one million deaths each year, Lung tumors isolated from adenocarcinoma patients of East Asian ancestry have a less complex genomic architecture than tumors from European patients, a new study has found.
Researchers from the Agency of Science, Technology and Research (A*STAR) in Singapore have now characterized the genomic landscape of this cancer among East Asians, generating a genomic and transcriptomic dataset encompassing more than 300 lung cancer patients of Chinese ancestry.
As they reported this week  in  Nature Genetics, they found that the tumor genomes were more stable and included fewer genetic alterations than lung adenocarcinoma genomes from European patients. Additionally, comparing transcriptome profiles, they uncovered an inflammation subtype specific to the East Asian patients that could point to a potential new treatment approach.

At the same time, the number and nature of driver mutations differed between tumors from East Asian and European patients. In East Asian patients, alterations affecting the EGFR, TP53, and KRAS genes were the most common driver mutations and nonsmokers had an average 2.08 driver mutations, as compared to an average 2.65 driver mutations among European nonsmokers. Additionally, East Asian patients had fewer copy number variations.

Together, these findings indicated that lung adenocarcinomas from East Asian patients typically have fewer genomic alterations and less complex genomic profiles than those from European patients.

By analyzing the transcriptomic profiles of the tumor samples, the researchers teased out three different lung cancer subclusters. Two of these were similar to the terminal respiratory unit (TRU) and proximal inflammatory subclusters previously found in European patients, but the third was specific to East Asians. That subcluster, dubbed TRU-I, was marked by the upregulation of inflammation-associated genes and increased immune infiltration. This phenotype could help identify patients who might be more likely to benefit from immunotherapy or immune checkpoint blockade treatment, the researchers wrote.

While they found that patients’ clinical features could predict their outcomes, they noted that genomic features could also predict patient survival. These predictions were more accurate for East Asian than European patients, which the researchers attributed to their more stable tumor genomes.

“This study elucidated a comprehensive genomic landscape of EAS [lung adenocarcinomas] and highlighted important ancestry differences between the two cohorts,” the researchers wrote in their paper.

Ph.D.; Professor in Pharmacology and Toxicology. Senior expert in theragenomic and personalized medicine and individualized drug safety. Senior expert in pharmaco- and toxicogenetics. Senior expert in human safety of drugs, chemicals, environmental pollutants, and dietary ingredients.

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