Unavoidable DNA Replication Errors Help Fuel Cancer

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Heredity and lifestyle get the most blame but new research suggests random chance plays a bigger role than people realize: Healthy cells naturally make errors when they multiply, unavoidable typos in DNA that can leave new cells carrying cancer-prone genetic mutations.

Gene mutations cause cancer but what causes the mutations?

You might inherit some mutations, like flaws in BRCA genes that are infamous for causing aggressive ovarian and breast cancers in certain families.

More commonly, the damage is caused by what scientists call environmental factors, the assault on DNA from the world around us and how we live our lives. There’s a long list of risks: UV light from the sun, other forms of radiation, cigarette smoke, certain hormones or viruses, an unhealthy diet, lack of exercise and obesity.

How Cells Make Typos?

Vogelstein said, new cells are formed when an active cell divides and copies its DNA, one cell turning into two. Every time DNA is copied, about three random mutations occur. Dr. Otis Brawley of the American Cancer Society, who wasn’t involved in the new research said, we all port these kinds of mutations and most don’t hurt us because they are in genes that have nothing to do with cancer or the body’s defense mechanisms point and fix the damage.

But sometimes the errors hit the wrong spot and damage genes that can spur cancerous growth or genes that help the cell spot and fix problems. Then the damaged cells can survive to copy themselves, allowing important mutations to gradually build up over time. That’s one reason the risk of cancer increases with age.

The Studying Findings

Thursday’s study follows statistician Cristian Tomasetti and 2015 research by Vogelstein that introduced the idea that a lot of cancer may be due to “bad luck” because those random DNA copying mistakes are more common in some kinds of cancer than others. Cancer prevention advocates worried the idea might sway people to give up on healthier lifestyles.

The duo analyzed mutations involved in 32 types of cancer to estimate that 66 percent of the gene flaws is due to random copy errors. Lifestyle and environmental factors account for another 29 percent, while inherited genes made up just 5 percent of the mutations.

Different Organs, Different Risks

The exact person can harbor a mix of mutations sparked by random DNA mistakes, environmental factors or heredity. The Hopkins team said, and which is the most common factor differs by cancer. For example, they estimate that random cell errors account for 77 per cent of critical mutations in pancreatic cancer – while still finding some caused by lifestyle risks like smoking. And the random DNA errors caused nearly all the mutations leading to childhood cancers, which is not surprising because youngsters have had little time to be exposed to environmental risks.

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