An international team of scientists for the first time, completely deciphered the genetic information 38 types of cancer cells, making an exhaustive catalog of DNA mutations leading to the development of cancer, reports the BBC.
The unprecedented scale of the study “Analysis of the full genome of all types of cancer” (PCAWG) took more than 10 years. The meeting was attended by about 1300 geneticists from 37 countries, and its results were published in Thursday in two dozen scientific journals.
According to the scientists, the causes of cancer can be compared with a puzzle, consisting of 100 thousand pieces. To date, we have tried to collect the overall picture, having only one fragment, and only now can look at it as a whole.
“With the help of information collected about the origin and development of tumors, we can develop new ways of early diagnosis of cancer, more targeted therapies and to treat patients with great success,” said a member of the coordinating Committee PCAWG Lincoln Stein.
Russian service Bi-bi-si briefly (in 100 words) and a little more (500 words) explains the essence of this unprecedented work and how it can revolutionize Oncology.
In 100 words
The cause of any cancer — mutations in DNA. However, scientists know little about where and why there is a breakdown of the genetic code, leading to the emergence of cancer.
Project participants PCAWG fully decoded the genetic information of cancer cells almost 2800 patients suffering from 38 different kinds of cancer.
The result was several dozen discoveries — the number and exact location of the so-called driver mutations (i.e. leading to tumor development) to unexpected genetic matches at cancerous cells of different tissues.
Including revealed that a predisposition to some types of cancer may develop for decades before diagnosis — sometimes in childhood.
Cancer is not one disease arising in various organs, and the common name for two hundred different diseases proceeding on the same scheme. One of the tissue cells mutates and begins to divide uncontrollably and forming a tumour.
Failure occurs at the gene level, but until today, trying to understand its possible causes, the scientists analyzed mainly only “useful DNA” — the part of the genome, which encoded proteins and which is only about 2% of all hereditary information.
The remaining part of the genetic code, known as “junk DNA” did not arouse much interest because it contained in it the information is not responsible for the production of proteins — the building materials of cells and in General were long considered vestigial (that is, accumulated in the process of evolution, but lost useful features).
The term “junk DNA” was introduced about 50 years ago and later found not quite correct, when it was discovered that some pieces of “useless” genome perform other essential functions to maintain cell life.
It was decided to decipher the genetic information of cancer cells as a whole, to track changes in non-coding genes.
As a result, scientists have discovered thousands of genetic mutations and described more than 80 processes leading to breakage of the genetic code. Some of them are caused by age-related changes, others are inherited, others may be associated with harmful habits or diet.
One of the main discoveries is that the same type of cancer can cause completely different sets of mutations. In lung cancer cells was detected up to 100 thousand mutated genes, and in some samples of childhood cancer mutations could be counted on the fingers.
“The most surprising discovery is how much the cancer genome of one patient differs from the genome of cancer cells of another,” said a member of the coordinating Committee PCAWG Peter Campbell.
However, have been identified and unexpected coincidences. For example, the same drivernya mutation may lead to development of breast cancer in women or prostate cancer in men. And that means that treatments designed for breast cancer, may be effective in the treatment of prostate cancer.
Some discoveries enable much earlier diagnosis of the disease. In particular, it was found that some types of cancer begin to form at the genetic level long before the development of the tumor, sometimes several years or even decades.
“This shows that we have much more opportunity of early intervention [in the situation] than we previously thought,” says Campbell.
In addition, compiled by the research catalogue of mutations will help to avoid setting the wrong diagnosis, sometimes due to the overlap of symptoms of different types of the disease.
However, 5% of the samples of the cancer cells did not have identified driver mutations — this means that the exact location of the critical failure of the genetic code was yet to be determined.
“If we understand what happens to our healthy bodies with aging that causes mutations to accumulate, why some clones are propagated indefinitely, and some fade away, as this balance is affected by lifestyle, then we will be able to come up with ways of early intervention to prevent or slow the development of incurable cancers,” concluded Professor Campbell.