Two novel genetic mutations that occur in 71 percent of malignant melanoma tumors have been discovered by scientists.
The mutations, detected in a part of the cancer genome that controls genes but not in the genes themselves, could aid understanding and lead to treatment of one of the world's most lethal cancers or stop its progression.
It "represents an initial foray into the 'dark matter' of the cancer genome," said Dr. Levi Garraway, of the Dana-Farber Cancer Institute and the Broad Institute of Harvard and Massachusetts Institute of Technology (MIT).
"In addition, this represents the discovery of two of the most prevalent melanoma gene mutations," he said of the findings, which were part of two studies published Thursday in the online edition of the US journal Science.
The researchers said the cancer-associated mutations were the first to be discovered in the vast regions of DNA in cancer cells that do not contain genetic instructions for making proteins -- the mutations are located in non-protein-coding DNA that regulates the activity of genes.
The mutations were discovered when the scientists sifted through data from whole-genome sequencing of malignant melanoma tumors.
Unlike "whole-exome" searches that examine only the protein-coding DNA of a cell's genome, whole-genome searches scan all of the DNA, including the non-coding regions.
In analyzing whole-genome data, the researchers found the two mutations in 17 of 19 (89 percent) of the tumors. They then examined a larger number of melanoma tumors and found the two mutations in 71 percent of them in total.
The researchers said the two mutations are present in cells found in liver and bladder cancers.