A replication error(.
According to the scientist, Johns Hopkins, two-thirds of all cancers are caused by errors of DNA replication. But wait, relieved to smoke!
We usually attributed to hereditary cancer genes such as BRACA1 or BRACA2 mutations responsible for cancer of the breast, ovaries and prostate. Or lifestyle, for example Smoking, or exposure to chemicals or radiation, says Big Think.
A new study published in the journal Science, however, relies on an ordinary accident.
The researchers say that the vast majority of cancer types – it is simply a mistake – an error in DNA replication. Thus, the development of cancer in many cases, inevitable. CEO Bert Vogelstein and mathematician Cristian Tomasetti in the cancer Center im. Johns Hopkins Kimmel away conducted a study on earlier, and came to the same conclusion.
To reproduce cells divide. Usually errors in the copies of DNA form a little and this causes problems. But if it happens more than once in a gene that causes cancer, the disease may take root, and the cell will become cancerous.
Vogelstein, and Tomasetti wanted to know how often replication errors are a major factor in the development of cancer and how it affects tobacco, pollution, inherited mutations and other factors. These researchers found that in fact the risk associated with the number of divisions of stem cells in the particular body.
Areas with a large number of stem cells (the colon) are at higher risk of developing cancer. And those who have little divisions of stem cells (brain), the risk is much less.
To conduct the study the researchers collected data from multiple databases. They then developed a mathematical model to estimate how many cancer cases are due to genetics, replication errors, DNA and the environment. The researchers found that the replication errors caused a whopping two-thirds of all cases.
Statistics varies depending on the type of cancer. As for lung cancer, 65% are caused by mutations caused by the environment, and only 35% of replication errors.
When prostate cancer is more than 95% of cases are caused by errors in DNA replication. The vast majority of cancer cases in children are due to replication errors.
After studying 32 different types, the researchers determined that 66% of all cancers were caused by the accident, 29% were caused by environmental reasons, and 5% inherited mutation.
One of the problems, according to critics, is that these data are depressing patients. Why do they have to lead a healthy life, if they can still get cancer?
42% of cases can be prevented, and these results do not change, says Vogelstein.
Vogelstein, and Tomasetti decided to explore the data 69 other countries that were not represented in the latter study. Vogelstein also studied some works on the cancer genome sequencing, looking for mutations caused by environmental factors.
According to genetics, the environmental factors may have been overestimated.
“If we think about mutations as enemies, and all enemies are outside our borders, it is obvious how to get them to get inside. But if many enemies – in this case, two – thirds are actually residing within our borders, it means that we need a completely different strategy.”
Critics argue that they may have missed the influence of hormones. In addition, the influence of some factors, such as Smoking, can be quantified, but what about the air pollution in addition to tobacco use?
Geneticist John Hopkins hopes that these data can ease the guilt of patients and their loved ones. Cancer patients often blame their genes or unhealthy lifestyle. But knowing that most cases of accidental, may help to reduce self-blame that often accompanies the disease.
And what to do now?