Breast Cancer Mystery Frustrates Scientists: Electric Light Just Latest Of Many Suspects

Hartford Courant ^ | February 6, 2005 | William Hathaway

[billorites]

Richard Stevens wants to shed some light on the murky origins of breast cancer.

The University of Connecticut cancer epidemiologist says there still is no scientific consensus about why the incidence of the disease is so much higher in the developed world.

The literature on breast cancer is littered with discredited theories about environmental and lifestyle factors that may contribute to the onset of the disease.

"We knew more about the cause of breast cancer 20 years ago than we do today," Stevens said. "What we do know is that it must have something to do with industrialized society."

Only a few theories have withstood scientific scrutiny, and no single factor explains a great percentage of breast cancer cases.

But that hasn't stopped people from looking for new explanations.

Now, Stevens and a few other researchers are focusing on a little-known suspect - electric light.

Their theory that artificial light can cause breast cancer is simple. Prolonged periods of exposure to artificial light disrupt the body's circadian rhythms - the inner biological clocks honed over thousands of years of evolution to regulate behaviors such as sleep and wakefulness. The disruption affects levels of hormones such as melatonin and the workings of cellular machinery, which can trigger the onset of cancer, Stevens theorizes.

"Mankind has only been exposed to these light sources for 150 years or so," Stevens said.

So far, the theory is based largely on suggestive, but inconclusive, observational studies. For instance, night-shift workers such as nurses tend to be more prone to develop breast cancer than day-shift workers, and blind women are less likely to have breast cancer than women with sight.

In a recent study, Stevens and scientists at Yale University School of Medicine identified a possible genetic mechanism that could help explain how artificial light could trigger breast cancer. Pre-menopausal women with a variation of a "clock gene," which helps govern the regulation of the body's response to night and day, tend to have a higher risk of cancer.

"I'm not saying this is a cause, but that the evidence shows it is worth investigating," Stevens is quick to caution.

The fact that the origins of breast cancer still are being debated - and that new theories are emerging more than three decades after the United States declared a war on cancer - illustrates just how stealthy breast cancer is.

Scientists estimate that about nine out of 10 breast cancer cases are triggered by environmental and lifestyle factors rather than inherited risk. Smoking has long been identified as a cause of lung cancer, and a virus, human papillomavirus, causes cervical cancer.

But with breast cancer, researchers are not sure what lifestyle or environmental causes women should worry about.

Some widely circulated theories have little data to support them and have been largely rejected by the scientific community. Antiperspirants and wire bras fall into this category, according to the National Cancer Institute. In 2003, the institute convened 100 breast cancer experts who concluded there is no evidence that miscarriages or abortions increase the risk of breast cancer.

Yet epidemiologists such as Stevens say other risk factors must exist and they urge that more studies be conducted.

"We absolutely need studies," said Deborah Winn, chief of the clinical and genetic epidemiology research branch of the National Cancer Institute. "If we have those answers, we might have the potential to improve prevention."

While the number of deaths from breast cancer has declined over the years, the incidence of the disease has increased slowly over the decades in the developed world, most studies show. And when a woman from a low-risk country moves to a high-risk country, her risk of breast cancer increases as well.

That's why suspicion centered on factors such as diet or pollutants such as pesticides.

Scientists believed for years that high levels of dietary fat accounted for differences in the rates of breast cancer in the developed and undeveloped worlds. But fat has largely been exonerated in breast cancer, Stevens said. A recent study in the Journal of the American Medical Association showed that even a diet heavy on fruits and vegetables did not protect women from the disease. And while pesticides can cause cells in laboratory dishes to turn cancerous, they have never been conclusively linked in large-scale studies to clusters of breast cancer cases.

There are plenty of oddities in the breast cancer epidemiology studies. Obesity is a risk factor for women - but only after menopause. Prior to menopause, obese women tend to get breast cancer less often than thinner peers.

Science, however, does say with great certainty that at least one factor plays a crucial role in the development of breast cancer: the female hormone estrogen, said Dr. Melinda Irwin, assistant professor in the department of epidemiology and public health at the Yale University School of Medicine.

For instance, Irwin notes that girls who get their first periods early in life and women who enter menopause late in life - in both cases, increasing their exposure to estrogen - are clearly at greater risk of breast cancer than their peers. Women who give birth to children before the age of 30 have a lower risk of breast cancer than women who give birth after 30 and women who never become mothers at all. Women who take hormone replacement therapy are also at higher risk.

Irwin has also done research that suggests that exercise, which can lower estrogen levels, offers women some protection against the development of breast cancer.

But Stevens and others believe other elements of modern lifestyle and environment must play a role in increasing the risk of breast cancer.

In the mid-1980s, Stevens investigated connections between cancer and the use of electric power. The work helped set off a controversial debate over whether there was a link between electric power lines and the development of cancer. It got him thinking about the potential role of electric lighting.

For most of human history, people slept or rested during dark hours - and produced the hormone melatonin. Melatonin levels regulate circadian rhythms and may, some studies suggest, affect estrogen levels as well. Artificial light tends to disrupt those rhythms, with reduced levels of melatonin believed to lead to an increase in estrogen production.

The light theory of breast cancer has received a boost in recent years with the discovery of clock genes, a group of about eight genes that help regulate circadian rhythms. It turns out that clock genes play an important role in the activation of genes governing cell cycle regulation and apoptosis, or cell suicide. Malfunctions in these processes have been linked to the development of cancer.

But for now, the light theory is firmly on the fringe of scientific consensus.

Many scientists believe that the search for environmental and lifestyle triggers for breast cancer will not turn up one major villain, but many different culprits that account for small percentages of breast cancer cases.

"I think we will be hard-pressed to find a single etiology to breast cancer. A woman's body is so complex and exposed to so many different things," said Dr. Kristen A. Zarfos, assistant professor of surgery and medical director of the University of Connecticut Health Center Women's Specialty Health Program.

"It might be a combination of small effects of a lot of things we know about," Stevens conceded. "But if not, then what is it? It is frustrating that major drivers have just not emerged for breast cancer as they have for other major cancers."

[spetznaz]

As i explained in my post it is not the high stress levels that are important but the continuous stress levels. In days of yore stress was existent. It is still there in the 3rd world. But it is here in the developed world that a person wakes up stressed, goes through the day stressed, and goes to bed stressed.

Most people are under constant stress. And it is the perpetuality of it, not necessarily the magnitude, that is dangerous. It has actually been shown that constant stress is an almost certain harbinger of disease.

[nothingnew]

It is sad. Until the un and others send pubic edumakayshun over to these poor countries and lift the ban on DDT to stop malaria, and stop their heavy foot from clamping down on the throats of people they declare to be helping while keeping them in the dark ages..../sarcasm

FMCDH(BITS)

[redhead]

It would take me a while to find the source, butin the article, it was reported that they were able to determine that Monkey Virus-contaminated supplies were given in Utah and 10 other states in 1955. The article had to do with Chronic Fatigue Syndrome. I will search and see if I can find it for you.

[nothingnew]

And it is the perpetuality of it, not necessarily the magnitude, that is dangerous. It has actually been shown that constant stress is an almost certain harbinger of disease.

That's why a firm belief in Him, and His promise of an afterlife with Him, which I hold, relieves 99% of that stress. When all you do is struggle on this earth, with no hope of anything after, bare existence here offers little more than stress and despair.

JMHO

FMCDH(BITS)

[Capriole]

Diarrhea is one of the most common causes of child and infant mortality in the underdeveloped world. The kids can't retain any fluid, get dehydrated, and die. The sad thing is, they can be saved very easily, with some of the cheapest medications that exist; saving a baby's life can cost only a few pennies. The difficulty lies in delivering these drugs to extremely remote areas not served by hospitals, clinics, or health-care workers.

[mad_as_he$$]

Man this is the first I've heard of this one. Interesting info. Thanks

[muir_redwoods]

"Over 500 years ago, what passed for scientists back then, used to call breast cancer the nuns disease, because only nuns got it. There is a definite link between breast cancer and not nursing children. Abortion comes into play because you can't nurse an aborted child."

Maybe and it's only anecdotal but my wife, who died last march from breast cancer, nursed all three of our daughters. She never had an abortion either, BTW

[Harmless Teddy Bear]

In the developing world they may have their own stress levels, but they are never always at full blast.

Right. Never being quite sure where your next meal is coming from is very soothing.

[WVNan]

Well, nobody has guessed it yet, so I'll just throw this out there. Mammagrams. No way will they ever get me near one of those things.

[Askel5]

=== Richard Stevens wants to shed some light on the murky origins of breast cancer. The University of Connecticut cancer epidemiologist says there still is no scientific consensus about why the incidence of the disease is so much higher in the dev


Hey ... how about the birth control which jacks with her hormones incessantly?

You think we'll ever see this tack investigated? Strangely enough, there's plenty of scientific evidence supporting the connection already. Odd that it gets no play in the media (or funding from the goverment).

[ErnBatavia]

Not many people died of cancer a two hundred years ago--plague, pneumonia, infections, etc., got them first---

I don't imagine anyone 200 years ago had the slightest idea that "cancer" even existed...maybe that's why so many people died from 'consumption'.

[nothingnew]

Diarrhea is one of the most common causes of child and infant mortality in the underdeveloped world.

I do not doubt this.

See #42

What do you or others propose? These are 3rd world unedumakated natives that have been under the auspices of the un for decades. What the hell is anyone supposed to do about it? What? Send more money to their freakin'* (*word replaced) leaders to build more palaces and caviar for there "state" dinners? What in the hell do you propose? Do you want me to go over there and live with them and tell them not to crap in their own water? Tell them to stop believing in "the goddess of the holy mountain of goat's heads"?

What do you propose?

FMCDH(BITS)

[small voice in the wilderness]

BRAVO. Standing ovation to you, nothingnew! You give $$$ to the situation and the leaders get rich. You send food and medicine and the leaders get richer. How many years has this vicious circle been turning and they are no better off today than the first day we decided we could save them. Until they want to change their leaders and have the passion and wherewithall to see it through, nothing will change. Maybe this is what W. was talking about in his SOTU speech. We'll be there to help when democracy is the cry of the people. Regards, SVITW

[TASMANIANRED]

"We knew more about the cause of breast cancer 20 years ago than we do today," Stevens said. "What we do know is that it must have something to do with industrialized society."

This is total b/s. What did they do get stupid. Did they loose the research. Did they all just get amnesia. Mean while they refuse to research the legitimate link between breast cancer and abortion.

[TASMANIANRED]

You got it buster.

At the turn of the 19th century average life expectancy was 49.

The number one cause of death in young adult women was child birth.

[nothingnew]

Thanks. I need no BRAVO, it's just common sense. The UN has to be abolished before any progress can be made for these 3rd world people. The UN is the biggest roadblock to any advancement therein. Some people here have grandiose positions about "helping" these poor unfortunates, but like you said "Until they want to change their leaders and have the passion and wherewithall to see it through, nothing will change." You are quite correct in that, tho the wherewithall will not come until the UN is finished, for good.

FMCDH(BITS)

[TASMANIANRED]

It may not be the nursing as much as the hormone break that people have with repeated pregnancies.

With the menstrual cycle you have rising and falling estrogen/progesterone levels monthly.

With pregnancy early you have a rise in progesterone that helps sustain the pregnancy in the early months (morning sickness months) and then a fairly steady state hormone lvl until delivery. If you breast feed you may not have menstrual cycles for many months.

With 5 pregnancies you have 4.8 years without the monthly fluctuations in estrogen/progesterone lvls.

[spetznaz]

see my post 41.

[Capriole]

What do you or others propose? These are 3rd world unedumakated natives that have been under the auspices of the un for decades.

Actually, I'm working with an organization that's got a good way of approaching things. It's a charitable organization that's trying to work around the UN, in a discreet way. They've assembled extremely low-cost medications, some preventative meds and some treatment drugs, to deal with the most common causes of childhood disease, plus some cheap first-aid supplies. They offer simple training to people in the village about how to treat ordinary illnesses and when to try to transport a very sick child to civilization for treatment. The important thing is that (a) they're avoiding the UN and the usual mercenary delivery systems, and (b) they're making sure that the drugs aren't the kind that are desirable for the use of soldiers, so they won't be as likely to be stolen by the corrupt military. It's a great system.

[maine-iac7]

There's a much more believable hypothesis put forth in the book: "Dressed to Kill." by a husband and wife research team, Sydney Ross Singer and Soma Grismaijer.

Their premise is "Their interpretation is that tight clothing inhibits the proper functioning of the lymphatic system (an internal network of vessels and nodes that flushes wastes from the body) and leads to a buildup of carcinogenic compounds in the constricted areas."

They got deep into this research after she was diagnosed with breast cancer. I have read it and it makes a lot of sense - if the lymphatic system is restricted from doing it's job, it can cause illness.

Also, the "electric light" theorists pose that since more women in developed countries get breast cancer than people in primitive areas might be the link - well, women in the primitive area don't constrict their bodies with bras...

Sydney Ross Singer received a B.S. in biology from the University of Utah in 1979. He then spent two years in the biochemistry Ph.D. program at Duke University, followed by another two years at Duke in the anthropology Ph.D. program, receiving a Master’s Degree. He then attended the University of Texas Medical Branch (UTMB) at Galveston, Texas on a full academic scholarship, where he spent one year in the medical humanities Ph.D. program, and received an additional two years training in medical school. Soma Grismaijer received an associate’s degree from the College of Marin in the behavioral sciences, and a bachelor of arts from Sonoma State University in environmental studies and planning.)