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65% of Cancers Caused by Bad Luck, Not Genetics or Environment
BarbaraHudson writes The Wall Street Journal and the CBC are reporting that about two-thirds of cancers are caused by random chance. From the WSJ: "The researchers, from the Johns Hopkins University School of Medicine in Baltimore, analyzed published scientific papers to identify the number of stem cells, and the rate of stem-cell division, among 31 tissue types, though not for breast and prostate tissue, which they excluded from the analysis. Then they compared the total number of lifetime stem-cell divisions in each tissue against a person's lifetime risk of developing cancer in that tissue in the U.S." The correlation between these parameters suggests that two-thirds of the difference in cancer risk among various tissue types can be blamed on random, or 'stochastic,' mutations in DNA occurring during stem-cell division, and only one-third on hereditary or environmental factors like smoking, the researchers conclude. 'Thus, the stochastic effects of DNA replication appear to be the major contributor to cancer in humans.'" The CBC reports: "The researchers said on Thursday random DNA mutations accumulating in various parts of the body during ordinary cell division are the prime culprits behind many cancer types. They looked at 31 cancer types and found that 22 of them, including leukemia and pancreatic, bone, testicular, ovarian and brain cancer, could be explained largely by these random mutations — essentially biological bad luck. The other nine types, including colorectal cancer, skin cancer known as basal cell carcinoma and smoking-related lung cancer, were more heavily influenced by heredity and environmental factors like risky behavior or exposure to carcinogens. Overall, they attributed 65 percent of cancer incidence to random mutations in genes that can drive cancer growth."
Here's a link to the actual paper, and a pretty nice editorial from Science (as opposed to CBC).
The correlation between these parameters suggests that two-thirds of the difference in cancer risk among various tissue types can be blamed on random, or 'stochastic,' mutations in DNA occurring during stem-cell division, and only one-third on hereditary or environmental factors like smoking, the researchers conclude.
The article says,
By “chance” Tomasetti meant the roll of the dice that each cell division represents, leaving aside the influence of deleterious genes or environmental factors such as smoking or exposure to radiation.
The summary says 1/3 has smoking and environmental effects, while the article says the 1/3 doesn't have smoking and environmental effects.
Lately, slashdot summaries have gotten worse and worse and completely change what is being claimed.
Some animals are much better at suppressing cancer than others. Humans rank as one of the best at this, but other animals do even better.
This is why rats are poor models for cancer in humans. They have few of our defenses and are severely prone to cancer.
As I recall a great deal of effort has been spent attempting to prove the existence of "hidden variables" in Quantum Mechanics, yet to date virtually all evidence suggests that they do not exist, and that quantum-level events are truly random. What makes you think that future discoveries will fundamentally change that? Do you just not like the idea that there might be some option for choice in your life?
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Sure, anyone can get cancer no matter how healthily they live. But modern medicine is so absurdly and willfully blind to the role of nutrition that these conclusions can be largely dismissed by anyone who thinks for themselves.
Oh, hey, trace arsenic cuts breast cancer by FIFTY PERCENT.
What's that? Lithium in drinking water is also associated with a host of benefits? Say it ain't so..
Gee, getting some sunshine / vitamin D can lower risk of pancreatic cancer??
I could go on and on but what would be the point.. supplementation and the like is at best psuedo-science in the eyes of western medicine.. it's much more profitable to engage in "sick care" than to actually equip our bodies with the things it needs at some single percent of the cost.
Indeed. I seem to recall reading something several years ago claiming that the average person develops cancer many times in their life - it's just that most of the time the tumor doesn't survive for long, or never grows beyond microscopic size. It's not the starting that's the problem, it's the conditions that allow it to grow and spread dangerously.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The world population almost doubled since 1940 (http://en.wikipedia.org/wiki/World_population), not to mention our capacity to detect smaller and smaller tumors made the number explode. Before, people were dying, not they're dying from a diagnosed X or Y reasons. Not to mention our lifespan increased, which increased the likelihood of our body's to go AWOL.
It's 2/3 of all types of cancer, are random. Not 2/3 of all cases of cancer (excluding the most common ones).
bogus math. pointless conclusion.
There are lies
Damn lies
Then there are statistics
You seem to misunderstand: cancer requires more than a single mutation. At a bare minimum cancer needs a protooncogene mutation, and then typically also requires Knudson two-hit on at least one of the tumor suppressor genes. That, together, gets cancer started.
The angiogenesis and metastasis mutations (among others) happen later due to natural selection. Cancer is just evolution.
To restate: I have never heard of a single DNA point mutation from wild type that can cause cancer. Multiple mutations of specific types are required. The odds of this happening are increased because most adult cells are on "pause" in the cell cycle, so mutations can accumulate without causing immediate triggering of apoptosis.