Cancer Secrets
A large-scale genome study has revealed the secrets of cancer formation
Polina Gershberg, Naked Science
The largest study of the genetic basis of cancer in the history of science has shown that the analysis of non-coding DNA can help identify those types of this disease that are difficult to detect now. In addition, the development of oncological diseases can be diagnosed decades earlier than the methods used today allow.
More than 1,300 scientists participated in a multi-year study of genomic sequences of various cancers by the Pan-Cancer Project. During the project, the genomes of 38 types of cancer were sequenced from samples obtained from 2,800 patients.
The results of the study were published in 21 articles published in Nature Publishing Group. This is the largest and most complete study of the genetic foundations of cancer in the history of science, which reveals many important details: from the location of the driver mutations that trigger the processes of non-stop cell division, to the amazing similarity between neoplasms in different types of tissues.
Thousands of combinations of mutations associated with individual cancers have been identified, and more than 80 processes that trigger driver mutations have been identified. "With the knowledge we have gained about the origin and development of tumors, we can develop new tools and treatments for early detection of cancer, create more targeted therapies and treat patients more successfully," says Lincoln Stein of the Ontario Institute of Cancer Research, a member of the Pan-Cancer Project coordinating committee.
Most of the previous work of this kind focused on exons – DNA sequences encoding certain proteins. However, exons make up only 2% of human RNA. The Pan-Cancer Project was dedicated to the remaining 98% – the so-called introns, or non-coding DNA.
Research has shown that the early development of some cancers can begin decades before diagnosis – sometimes even in early childhood. According to the researchers, this shows that the "window of opportunity" for the use of anti-cancer therapy is much wider than previously thought. It was also found that mutation patterns and their location in the genome can identify up to 5% of cancers that cannot be diagnosed by standard methods.
The spread of the number of mutations associated with different types of cancer turned out to be extremely large: from single changes (some types of cancerous tumors found in children) to hundreds of thousands of mutations (in lung cancer). About 5% of tumors could not be associated with known driver mutations – they have yet to be detected.
Nevertheless, often pathological processes in different parts of the body are similar. "We may have a type of breast cancer and prostate cancer with similar driver mutations," says Joachim Weishenfeldt of the University of Copenhagen, one of the project participants. "It means that such patients can receive the same treatment."
From a practical point of view, the results obtained in the Pan-Cancer Project will help identify difficult-to-diagnose cancers, create more targeted treatment based on disease-specific mutations and conduct earlier diagnosis of developing tumors.
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