Genomic mapping brings new hope to lung cancer fight

SAN FRANCISCO — A form of lung cancer that kills 400,000 people annually worldwide could be attacked by targeting newly discovered genetic mutations, according to a study that mapped the tumours’ DNA.

Researchers found mutations in 11 genes from 178 squamous cell lung tumours they sequenced, including alterations previously linked to cancer growth, according to the study published Monday in the journal Nature. The findings also included variations in a gene, called HLA- A, that helps the immune system fight off irregular tissue in the body.

“To our knowledge, this is the first example of a tumour that has a genomic mechanism for evading an immune response,” Matthew Meyerson, co- leader of the team that made the discovery, and pathology professor at Dana- Farber Cancer Institute and Harvard Medical School in Boston, said in a statement. “This provides many new therapeutic opportunities for squamous cell carcinoma that would be suitable for clinical trials.”

The findings are encouraging for patients with squamous cell lung cancer because, unlike a form known as adenocarcinoma, there are no drugs available that target the DNA mutations that drive this malignancy’s growth. Patients with the adenocarcinoma form can be given drugs which target a mutation in the EGFR gene.

The study of squamous cell lung tumours found 90 per cent had an altered TP53 gene and 72 per cent had an inactive CDKN2A gene, both previously identified mutations, the study said. When these genes are switched off, cancer can grow uncontrollably.

The data are part of a broader project by the National Institutes of Health called the Cancer Genome Atlas, which is analyzing tumours and blood samples from 20 types of cancer.

One of the project’s earlier studies of ovarian cancer patients with a genetic mutation best known for its ties to breast cancer have found they have a higher survival rate than those without the mutation.