The catalogue of somatic mutations in a small-cell lung cancer genome (top) and the COLO-829 (malignant melanoma) genome (bottom). Image via Wellcome Trust Sanger Institute
Scientists at Great Britain's Wellcome Trust Sanger Institute made a
major breakthrough in cancer discovery, having identified all of the
genetic mutations that contribute to lung cancer
and melanoma, two of the most lethal cancers. We're not talking about
20 or so mutations... The genetic map for lung cancer contains more
than 23,000 mutations; malignant melanoma involves more than 33,000
Wellcome Trust Sanger Institute is one of several research institutes in ten countries involved in cataloging the mutations of several different kinds of cancer. As part of The International Cancer Genome Consortium, the US is working on mapping brain, ovarian, and pancreatic cancers. Japan is focused on liver cancer, India on oral cancers, China on stomach cancers... Britain, in addition to lung and skin cancers, is collecting genetic mutations for breast cancer.
It is expected to take more than five years to finish cataloging these cancer maps, but when they are complete, the information is expected to lead to a revolution in cancer treatments, because the maps make known exactly how cancers are caused and develop. For example, the scientists working on the lung cancer mapping were able to determine that the primary cause of lung cancer is cigarette smoke and, from the specific information revealed in the mutation patterns, that for each 15 cigarettes that are smoked, a typical smoker will acquire one new mutation.
Dr. Peter Campbell, who worked on the lung cancer research, reported that, "Most of the time the mutations will land in innocent parts of the genome, but some will hit the right targets for cancer." He added, however, that quitting smoking can reduce opportunity for the mutations, as eventually mutated genes can be replaced by new genes that are free of genetic errors.
In terms of cancer prevention, the mapping data will determine more specifically which lifestyle and environmental factors are contributory to each type of cancer.
sources: Wellcome Trust Sanger Institute; BBC News via U.S. News & World Report