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Most types of cancer traced to 'bad luck' rather than risk factors, say scientists
In the US, 6.9% of people develop lung cancer, 0.6% brain cancer and 0.00072% get tumors in their laryngeal cartilage at some point in their lifetime. 
“We should focus more resources on finding ways to detect such cancers at early, curable stages”, said researcher Christian Tomasetti Most types of cancer can be put down to bad luck rather than risk factors such as smoking, a study has suggested. US teams were trying to explain why some tissues were millions of times more vulnerable to cancer than others.
The results, in the Journal Science, showed two thirds of the cancer types analyzed were caused just by chance mutations rather than lifestyle. However Cancer Research UK said a healthy lifestyle would still heavily stack the odds in a person's favor.
In the US, 6.9% of people develop lung cancer, 0.6% brain cancer and 0.00072% get tumors in their laryngeal (voice box) cartilage at some point in their lifetime.
Toxins from cigarette smoke could explain why lung cancer is more common.
But the digestive system is exposed to more environmental toxins than the brain, yet brain tumors are three times as common as those in the small intestine.
The team at Johns Hopkins University School of Medicine and Bloomberg School of Public Health believe the way tissues regenerate is the answer.
Old tired cells in the body are constantly being replaced with new ones made by dividing stem cells. But with each division comes the risk of a dangerous mutation that moves the stem cell one step closer to being cancerous.
The pace of turnover varies throughout the body with rapid turnover in the lining of the gut and a slower pace in the brain.
The researchers compared how often stem cells divided in 31 tissues in the body over a lifetime with the odds of a cancer in those tissues. They concluded that two thirds of cancer types were “due to bad luck” from dividing stem cells picking up mutations that could not be prevented.
These cancer types included Glioblastoma (brain cancers), small intestine cancers and pancreatic cancers.
Cristian Tomasetti, an assistant professor of oncology and one of the researchers, said a focus on prevention would not prevent such cancers.
“If two thirds of cancer incidence across tissues is explained by random DNA mutations that occur when stem cells divide, then changing our lifestyle and habits will be a huge help in preventing certain cancers, but this may not be as effective for a variety of others.
”We should focus more resources on finding ways to detect such cancers at early, curable stages.“
The remaining third of cancer types, which are affected by lifestyle factors or a heightened family risk, include some of the most common: Basal cell carcinoma - a type of skin cancer made more common by too much UV exposure; Lung cancer - strongly linked to smoking; and Colon cancer - increased by poor diet and family risk genes.
Separate research by Cancer Research UK shows more than four in 10 of the total number of cancers were down to lifestyle.
Dr Emma Smith, senior science information officer at the charity, told the BBC: ”We estimate that more than four in 10 cancers could be prevented by lifestyle changes, like not smoking, keeping a healthy weight, eating a healthy diet and cutting back on alcohol.
“Making these changes is not a guarantee against cancer, but it stacks the odds in our favor.
”It's vital that we continue making progress to detect cancer earlier and improve treatments, but helping people understand how they can reduce their risk of developing cancer in the first place remains crucial in tackling cancer.” (BBC).-
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Read all commentsI remember about 50 years ago I had to attend an examination of a new imported piece of scientific equipment at the Royal Beatson Hospital in Glasgow. This hospital specialised in the treatment of cancers. The chief scientific officer explained what the equipment was used for and in a general discussion about the causes of cancer he told me this which I have never forgotten.
Jan 04th, 2015 - 12:55 pm 0Every year, he said, we are being exposed to new chemical compounds which do not exist naturally in nature. The human body has developed over hundreds of thousands of years alongside naturally occurring substances some of which are carcinogenic. We are now exposing ourselves to new compounds which the human body has never had to deal with and we do not know the long term effects on our physiology.
Think of the number of chemicals and products which were common and have now been banned from use. DDT, Agent orange as used in Vietnam and available as a garden weedkiller, trichloroethylene used in dry cleaning.
Asbestos was considered safe and now any building with asbestos has to be closed and specialist teams in NBC clothing brought in to remove it.
It makes you wonder what else is ticking away !
#1 Clyde15 indeed what else is ticking away
Jan 04th, 2015 - 05:42 pm 0Most types of cancer traced to 'bad luck' rather than risk factors, say scientists:
Peronism, the earliest Neoplasm which was first known about in mid 1940‘s Argentina, has over time mutated into Kirchnerism Necrosis of normal life, with a nasty and variant offspring the malignant tumor Cámporaism. All are clearly seen in the social laboratory that is the Argentine.
There are some teratoma, more familiar as Castro-Timerman-Filmus, although not especially harmful as they are more dense and dopey.
Bad luck Argies. Get yourselves to a working MRI scanner.
They cant afford one,
Jan 04th, 2015 - 07:50 pm 0that one reason they would like to get to the islands,
to steal,,,,sorry--borrow the islanders..
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