'Driver' mutations may promote survival of cancer cells

NEW YORK: Researchers have discovered new genetic mutations that may promote the survival of cancer cells, and a clearer understanding of how some cancer cells are able to resist treatment, researchers said.

"All cancers are caused by genetic damage, mutations to key genes that control the lives of cells," said co-author of the study, Lucio Miele from the Louisiana State University in the US.

"Mutant genes that cancers depend upon for survival are called 'driver' mutations."

For the study, published in the journal PLOS ONE, researchers tested genes in 44 cancers that no longer responded to therapy. The tumour types included breast, lung, colorectal, sarcomas, neuroendocrine, gastric and ovarian among others. 

The researchers found that these advanced cancers had selected many new possible "driver" mutations never described before, in addition to drivers already known -- the cancers had evolved new driver mutations to become resistant.

In some cases, evidence was found that an individual cancer had evolved two or even three drivers in the same gene, a sign that multiple cancer cell clones had evolved in the same tumour that had found different ways of mutating a particularly important gene. 

Many of these new genetic mutations are in functional pathways that can be targeted with existing drugs, the researcher said.

"These findings imply that genomic testing should be performed as early as possible to optimise therapy, before cancers evolve new mutations, and that recurrent cancers should be tested again, because their driver mutation may be different from those that existed at diagnosis," Miele noted.