Thursday, November 24, 2016

Smokers & Non-Smokers Show Different Cancer Mutation Patterns

A study explains that DNA damages offer hints to help find malignancies in different types of tissues. DNA in malignant tissues of smokers shows a mutation pattern that is significantly different from those in the malignant tissues of those that are nonsmokers. This new study explains how smoking has a correlation with various types of cancer which enhances several types of DNA damage. A mutation in our DNA can arise more naturally in someone's lifetime, but some genetic changes --such as those caused by smoking -- significantly increase the risk of certain cancers. Fortunately, scientists have recognized many patterns of DNA mutations that routinely show up the tissues of certain cancers. The identified patterns that appear over and over again in a tumor DNA, can behave as a signature of the underlying mechanism that caused the mutation, which will offer clues to how different cancers can attack.lady smoking

Ludmil Alexandrov, a cancer geneticist said that although smoking's link to cancer has been known for many years, it was a mystery to him as to why smoking will increase risks of cancer like the bladder or kidney, tissues that were not exposed to smoke. Alexandrov and his team of researchers found many differences in the number of manipulated DNA signatures in the malignancies of smokers compared to those that had the same type of cancer but did not smoke. Smoking can leave permanent mutations, it destroys the genetic material in many cells in the body. Alexandrov collected DNA from more than 5000 people which represented 17 cancer for which smoking was a known risk factor. Almost half of the samples were from smokers. Signature 4 was mostly found in the people who smoked but occurred far less in nonsmokers. Signature 4 showed up in cancers of the oral cavity, but researchers were not sure why these tissue's which are directly exposed to smoke didn't have a heavy mutational load. DNA damage in smokers differed from those that didn't smoke in an another suite of mutation known as signature 5. The cause of signature 5 is still unknown, but researchers did determine that the amount of signature 5 mutations is like a clock, it increases with age. Researchers also took into account the amount of tobacco smoked, they discovered that the number of mutations in some diseases was linked to smoking a pack a day for one year. A pack a day for one year leads to 150 mutations in a lung cell, 97 in a larynx cell, 39 in the pharynx, 23 in the oral cavity, 18 in the bladder and 6 in a liver cell. 

"When someone has cancer, we can only see what is happening right now, we do not know what happened 20 years ago when that cancer was just one cell," says cancer biologist GerdPfeiffer. I completely agree with Pfeiffer on that because these signatures can give us a clear idea of what might have happened years ago.

Smoking is actually giving one benefit, and that is to figure out why it increases the risks of cancer. With this idea, we can make more experiments on how it can decreases the risks too.

1 comment:

  1. I’m not surprised by these findings that the mutation pattern in malignant tissues of smokers and nonsmokers are different. I am surprised to see the number of mutations in the different places of the body even where the smoke did not reach. The signature 5 mutation is worth looking into in further research in order to determine the cause of the mutation. Like the affects of smoking, this mutation increases with age which I didn't know was possible which is interesting.