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Stanford Medicine


Cancer, Public Health

Why are so many lives affected by cancer?

rope bridgeI’m a regular reader of The New York Times obituaries. I don’t read them because I’m a morbid person; rather, the obituaries offer me a window into history reflected through the lives of accomplished individuals.

One day in August, I was struck by the photos accompanying obituaries of three women, who all appeared to be relatively young. The 59-year old was co-founder of a nonprofit, Common Sense Media, committed to helping families navigate through entertainment, media and technology arenas. The 64-year old was an Olympic Equestrian medalist winning the U.S. title of rider of the year three times. And the 56-year old was a Harvard scholar and artist whose work explored myth, mystery and identity.

Each shared another characteristic besides a relatively early death: cancer.

These losses of life – far too early – brought back memories of the opening words of a story set more than 300 years ago: “On Friday noon, July twentieth, 1714, the finest bridge in all Peru broke and precipitated five travelers into the gulf below.” That was from Thornton Wilder’s 1927 novel, The Bridge of San Luis Rey. In this story, a friar, who observed the collapse of the rope bridge, wanted to know about the events that led up to each person being on the bridge at that time. Through extensive interviews, he was determined to understand the circumstances that led to their deaths.

A similar question haunts us in 2015: Why will one of every two of us, on average, “fall off the bridge” – that is, have our lives impacted by cancer? Over the past few decades, we’ve gained knowledge that allows for a safer life journey. We know that one half of cancers can be prevented by measures such as not smoking, protecting against excessive sun exposure, getting regular prostate check-ups, lowering obesity, reducing alcohol consumption and engaging in regular exercise.

We appear to be making progress. A recent report revealed that fewer people in the greater San Francisco Bay Area are getting cancer, and fewer are dying from it. More specifically, in the most recent 25-year period for which data are available, the occurrence of all new cancers combined declined by 13.2 percent.

Such news is encouraging. Yet, while advances in cancer treatment may allow more of us to cross our bridges safely and to help us heal if we fall, we must do better. We haven’t yet unlocked the mysteries of cancer. Indeed, the task is more daunting than we ever imagined; we now know that there are more than 200 diseases that we call cancer. We need to look for answers with large-scale genomics (looking at the structure and mapping of genes), bioinformatics (analyzing complex data, such as genetic codes) and computational biology (using data to study relationships in the biological system). We need to develop a better understanding of health disparities (across socially disadvantaged populations) and to drill down to an individual’s unique molecular and genetic characteristics.

For asking troubling questions which threatened authority, the friar in The Bridge of San Luis Rey was tried by the Inquisition and burned at stake. I would only hope that those of us who are probing deeply to prevent the scourge of cancer will be treated more kindly by society (and, especially, by funding agencies).

Donna Randall, PhD, is chief executive officer of the Cancer Prevention Institute of California, a partner of the Stanford Cancer Institute.

Cancer, Health Policy, NIH, Public Health

Draining the cancer swamp

Draining the cancer swamp

4011473415_46405053bd_zThere’s an old adage that applies to many difficult situations that we face in life: When you’re up to your armpits in alligators, it’s difficult to remind yourself that you should have drained the swamp.

I’ve come to view cancer as a vicious predator lurking in dark waters, eager to attack one out of two of us in our lifetimes. Cancer is the second most common cause of death in the United States.

Looking at the current national funding model for cancer research, I wonder if society has lost track of a vital goal: preventing cancer, not just treating it. Wouldn’t it be better if we prevented cancer in the first place? Cancer prevention would reduce the devastating physical, psychological, emotional, social and economic burden placed on patients, their families and their friends.

As he stepped down from the role of Director of the National Cancer Institute, Harold Varmus, MD, spoke about the deep complexity of cancer and the tremendous amount of basic research that needs to be done. While recognizing the need for clinical testing, he also called for more pioneering discoveries into who gets cancer, where and why.

The financial constraints facing scientific research force us to make difficult choices. Right now, our current health-care model prioritizes “identifiable individuals” over “statistical individuals.” Identifiable individuals are those real persons in distress who have been diagnosed with cancer. They need treatment, and we are highly motivated to help cure them. The cost of doing so, however, is high: The average monthly cost of cancer treatment has more than doubled to $10,000 over the last decade. Of course, we are willing to pay the costs – these victims are our mothers, our fathers, our sons and our daughters.

Statistical individuals are those who may be at risk, but they may not know it. They may never know that scientific research “rescued” them from a devastating disease. Through prevention measures enacted by individuals themselves (e.g., getting more exercise, avoiding tobacco use) or by society (e.g., limiting chemical exposures in the environment, banning the use of tanning beds for minors), these individuals may be able to escape the scourge of cancer.

When making choices about where to invest limited dollars, it is so much easier to say “no” to statistical people rather than real people.

I don’t advocate taking money away from cancer treatment, but I do advocate a greater investment of federal dollars in research that leads to reducing the incidence of cancer in the healthy population. By tracking and analyzing patterns and trends of cancer, we can identify potential risk factors and inform individuals and communities about positive changes they can make toward living cancer-free lives.

It is estimated that over 50 percent of the 585,720 cancer deaths in the U.S. in 2014 were related to preventable causes. As such, federal dollars directed toward statistical individuals will save both money and lives.

We need to drain the swamp. Our ultimate societal goal shouldn’t be to treat cancer more effectively, but to prevent it altogether. We need to intervene as early as possible in the trajectory of cancer. By doing so, we will greatly reduce the extent and depth of human suffering.

Donna Randall, PhD, is chief executive officer of the Cancer Prevention Institute of California.

Photo by William Warby

Cancer, Health Policy, In the News, Public Health, Women's Health

Health hazards in nail salons: Tips for consumers

Health hazards in nail salons: Tips for consumers

3044578995_fe5151de75_zAfter exercise class the other day, my friend asked if I wanted to grab coffee and get our nails done. With nail salons on what seems like every block, having a manicure or pedicure is as easy as grabbing a latte. You don’t need an appointment and you’re done in less than an hour.

But this convenience comes at a cost. A recent investigative report in the New York Times exposed the not-so-bright side of nail salons. The articles have raised awareness of poor working conditions and health risks, and they’ve generated a vigorous public dialogue.

“It got people talking and that’s a good thing,” said Thu Quach, PhD, MPH, a research scientist at the Cancer Prevention Institute of California and research director at Asian Health Services.

An epidemiologist, Quach has spent much of her career studying harmful chemicals in nail care products and their health impacts on nail salon workers, a vulnerable workforce that is mainly comprised of low-income immigrants. In research studies she has conducted over time, Quach identified symptoms commonly experienced by salon workers, including dizziness, rashes, and respiratory difficulties, and more serious reproductive health effects and cancer.

“Unfortunately, the risks associated with chronic, long-term exposure to chemicals used in nail products have been little studied,” Quach said. “We know workers are exposed every day and their health is at risk – this is an important focus of my ongoing research.”

The California Healthy Nail Salon Collaborative (CHNSC), convened through Asian Health Services, educates salon owners, workers and consumers about health and safety issues, and advocates for stronger protections for all. Quach, who has been a CHNSC member since its inception, works closely with other members to address worker health and safety using an integrated approach of community outreach, research, and policy advocacy to address health and safety. The CHNSC has worked at the local, state, and federal level to promote changes.

Encouraging counties and cities to adopt the healthy nail salon program is a first step in their local approach. Participation is voluntary and to date three counties and one city have committed: Alameda, San Francisco, San Mateo, and Santa Monica. These counties provide training and formal recognition for salons that participate. Santa Clara has the program in the works and many salons throughout the state participate in healthy initiatives on their own.

In addition to local municipalities taking action, some manufacturers have stepped up to omit the “toxic trio” – dibutyl phthalate, toluene and formaldehyde – from their formulations. But despite rising awareness of the health hazards posed by these chemicals, many products still contain them and there is no regulatory oversight.

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Cancer, Public Health, Science

Research institute or detective agency? Investigating the “perp” known as cancer

Sherlock Holmes2After graduating from college, I accepted a job as a white-collar crime analyst for the Iowa Bureau of Criminal Investigation. It was an exciting first job for a 21-year old. I worked closely with a team of highly trained and dedicated public safety officers to help detect and prosecute white-collar criminals. My specific role was to identify patterns in criminal activity and assist in building a narrative so others could understand how and why the crime was committed.

Little did I know how closely that job would parallel my current one.

Forty years later, I find myself leading a different type of “detective agency,” the Cancer Prevention Institute of California (CPIC). CPIC employs highly skilled researchers who function a lot like private investigators. They are epidemiologists – scientist-sleuths who examine trends and patterns in the population to identify risk factors and causes and effects of disease, and their work is anything but “elementary.”

As curious and persistent as any detective, epidemiologists are driven to solve challenging public-health cases. At CPIC we pursue understanding the traits and tendencies of a particular perpetrator: cancer. For example, our researchers look at how cancers occur geographically, examining incidence and mortality rates by specific regions across California and the U.S.

“Data! Data! Data!” Sherlock Holmes cried impatiently in The Adventure of the Copper Beeches. “I can’t make bricks without clay.” Well, like Holmes, our scientists also need data; lots of it. CPIC maintains the population-based registry of all Greater Bay Area cancer cases, as mandated by California state law. The registry is a deep source of information on the approximately 30,000 new cancer cases diagnosed each year across our nine-county area. To date, more than 850,000 Greater Bay Area cancers have been registered. Through this and other data bases, our researchers are able to “investigate” a wide range of cancers, from the most common to the rarest forms, and examine important evidence linking cancer risk with such factors as race/ethnicity, genes, environment, migration status and lifestyle.

Has our scientists’ sleuthing paid off? Definitely. To illustrate, CPIC’s researchers and their colleagues at the Stanford Cancer Institute (SCI) recently found that a double mastectomy does not improve survival over the less invasive option of lumpectomy plus radiation for the average breast cancer patient, contributing important information for breast cancer patients and their physicians worldwide as they evaluate their treatment options. Research conducted by CPIC and SCI scientists also detected alarming rates of deadly melanomas in Californians, as cited in 2011 legislation that made California the first state to ban the use of tanning beds by minors. CPIC researchers also discovered that California nail salons had higher than expected levels of carcinogens, identifying a need for better health standards.

And, yes, just like Adrian Monk or Colombo, we have some quirky scientists who help make coming to work both mighty interesting and very fulfilling. If you come to visit us at CPIC, you just might spy a rumpled raincoat or two.

Donna Randall, PhD, is Chief Executive Officer of the Cancer Prevention Institute of California.

Previously: Breast cancer patients are getting more bilateral mastectomies – but not any survival benefit, Gel polish: What risks lie beneath painted beauty? and New law: No more tanning beds for California teens
Photo by dynamosquito

Cancer, Research, Stanford News, Surgery, Women's Health

Breast cancer patients are getting more bilateral mastectomies – but not any survival benefit

Breast cancer patients are getting more bilateral mastectomies - but not any survival benefit

woman looking out window2The most common cancer diagnosis you or a woman you love is likely to receive is early stage breast cancer, probably after detection by mammogram. One would think that given the regularity with which it’s diagnosed, treatment options for early stage breast cancer would be streamlined. Unfortunately, this isn’t the case.  There’s a staggeringly large menu of potential surgeries and treatments from which a patient and her doctor must choose, each with their own risks and benefits. Not including all of the different hormone blocking and chemotherapies, patients must pick one of three surgeries, shown here in order of escalating invasiveness and risk of complication:

  • Breast-conserving surgery (removal of the tumor only), followed by radiation
  • Single mastectomy (removal of the entire affected breast and any affected lymph nodes)
  • Bilateral mastectomy (the above plus the the unaffected breast)

One also would assume that the medical evidence base providing the benefits to the risk/benefit equations for each surgery would be large and up-to-date. Surprisingly, it is not. The randomized trials comparing lumpectomy and single mastectomy were conducted 30 years ago, and they showed similar risks of death. There has not been (and probably will never be) a randomized trial comparing bilateral mastectomy to one of the less invasive choices for healthy women. Angelina Jolie and other women positive for the breast cancer genes (BRCA1 and BRCA2) are in a different situation. For these women, clinical studies have observed a survival benefit after prophylactic mastectomy. For the 99 percent of women without mutations in these or other high-risk genes, existing trial data do not speak to current trends.

Even after accounting for [numerous factors], we found no evidence of lower mortality for women who had bilateral mastectomy in comparison to breast-conserving surgery

The complexity of choosing a breast cancer surgery – and how evidence should play into that choice – has been a hot topic in the last two months, after the publication of a large study calculating (based on predictive models) that bilateral mastectomy ultimately provides little to no improvement  in life expectancy as compared to a single mastectomy. Soon thereafter, on the New York Times’ opinion page, journalist Peggy Orenstein discussed the emotional reasons why women remove their remaining healthy breast, but firmly labeled bilateral mastectomy as  the wrong approach to breast cancer, saying, “It’s hard to imagine… that someone with a basal cell carcinoma on one ear would needlessly remove the other one ‘just in case’ or for the sake of ‘symmetry’.” Other journalists shared why they chose bilateral mastectomy knowing that it wouldn’t necessarily save their life.

To improve the evidence regarding outcomes after the three surgery types, our team at the Stanford Cancer Institute and the Cancer Prevention Institute of California used one of the largest cancer databases available: the cancer registry for the entire state of California. We tracked all 189,734 women diagnosed with stages 0-III breast cancer from 1998-2011 to learn which surgeries they were undergoing for breast cancer treatment and how long they survived afterwards.  These are all women who should have been eligible for breast conserving surgery with radiation. Our results were published today in the Journal of the American Medical Association today and have already received media attention.

We found that bilateral mastectomy for early stage breast cancer increased from 2 percent in 1988 to more than 12 percent in 2011.  The rate of increase was fastest among women younger than age 40 at diagnosis, among whom over one-third of those diagnosed in 2011 had a bilateral mastectomy. Bilateral mastectomy was more often chosen by non-Hispanic white women, those with private insurance, and those who received care at a National Cancer Institute-designated cancer center; while unilateral mastectomy was more often chosen by non-white women and those with public/Medicaid insurance. Even after accounting for characteristics of the women themselves, their tumor types, and their hospitals, we found no evidence of lower mortality for women who had bilateral mastectomy in comparison to breast-conserving surgery. Surprisingly, we found that women who underwent unilateral mastectomy had higher mortality than those who had the other two surgery types. We concluded that despite the growing popularity of bilateral mastectomy, it likely does not provide a better outcome than a less invasive procedure.

These data and the public response to them underscore the need for more updated and more personalized information regarding outcomes after common surgeries. Ideally, these would be accessible real-time by patients and their doctors in easily-understood formats.

Christina A. Clarke, PhD, is a Research Scientist and Scientific Communications Advisor for the Cancer Prevention Institute of California, and a member of the Stanford Cancer Institute.

Previously: At Stanford event, cancer advocate Susan Love talks about “a future with no breast cancer”, Exploring the reasons behind choosing a double mastectomy and Researchers unsure why some breast cancer patients choose double mastectomies
Photo by Alex

Cancer, Dermatology, Public Health, Research, Stanford News

Melanoma rates exceed rates of lung cancer in some areas

Melanoma rates exceed rates of lung cancer in some areas


Californians, step away from the beach and grab a hat and sunscreen. Our team of researchers from the Cancer Prevention Institute of California/Stanford Cancer Institute released a new report (.pdf) this week documenting the rapidly growing burden of melanoma in Marin County, California. This small, homogenous (and wealthy) county just over the Golden Gate Bridge from San Francisco has been the focus of cancer studies before, as high rates of breast cancer were first reported there in the late 1990’s (rates declined there as in the rest of the country in 2003 when women stopped taking hormone therapy).

Our most recent cancer registry data show that rates of malignant melanomas in Marin County are 43 percent higher than the rest of the San Francisco Bay Area and 60 percent higher than other parts of California among non-Hispanic whites, who because of their fairer skin tones are diagnosed with melanoma at 20-30 times the rate of other ethnic groups. Also of concern is that the death rate due to melanoma is 18 percent higher in Marin whites than whites in other regions, a significant difference not seen before. Most of the elevated rates are limited to persons over age 65, especially men.

The Bay Area news media reported our findings as front-page news. Most coverage centered on the question of why the rates are so much higher in Marin County. Our best guess is that the higher average socioeconomic status of its residents corresponds to a higher proportion of people with the known risk factors for melanoma: fair complexion (pale skin, blonde or red hair, blue or green eyes) and a history of “intense intermittent” sun exposure over their lifetimes (exposure in big doses like you might get on a beach vacation in the winter).

However, it is also likely that better access to health care and skin screening has resulted in earlier diagnosis, a notion confirmed by the higher proportion of melanomas in Marin County caught when thin and more curable. Local dermatologists reacted to the statistics with some surprise, but didn’t change their standing advice regarding skin cancer prevention: talk to your doctor about skin screening and stay sun safe by wearing hats, long-sleeves and broad-spectrum sunscreen during outdoor activities.

One statistic mostly overlooked by the media was our finding that melanoma is now the second most common cancer diagnosed in men living in Marin County, as rates have surpassed those for lung cancer. This pattern is very different than that observed for whites in the US and world, for whom prostate or lung are first, and melanoma is ranked much lower. With one of the most successful public tobacco control efforts in the world, most populations in California have seen rapid declines in the incidence of smoking-related cancers of the lung and respiratory system.

Unfortunately, it seems for older white persons in Marin County (as well as parts of Utah and Hawaii, where smoking rates have also declined), melanoma and skin cancers represent a major—and relentlessly growing—cancer threat. Perhaps putting down the cigarettes was accompanied by more time at the pool or beach without adequate sun protection. Although California was the first state to ban tanning bed use by minors, we should look to Australia and other countries also battling rising skin cancer rates for innovative new policies and strategies for encouraging safe sun exposure in our at-risk communities.

Christina A. Clarke, PhD, is a Research Scientist and Scientific Communications Advisor for the Cancer Prevention Institute of California, and a member of the Stanford Cancer Institute.

Previously: Beat the heat – and protect your skin from the sun, Working to protect athletes from sun dangers, As summer heats up take steps to protect your skin, Stanford study: Young men more likely to succumb to melanoma and How ultraviolet radiation changes the protective functions of human skin
Photo by stefan klocek

Cancer, Public Health, Stanford News

Can repackaging aspirin get more people to take it daily for prevention?

Can repackaging aspirin get more people to take it daily for prevention?

aspirinNot many over-the-counter drugs can substantially improve your health. However, according to the U.S. Preventive Services Task Force, aspirin can reduce the risk of cardiovascular disease for some people. There is also building evidence that daily low-dose aspirin reduces risk of breast cancer, colon and other gastrointestinal cancers, and may even slow down dementia.

When a doctor agrees that the benefits of daily low-dose aspirin outweigh the potential side-effects, aspirin can be an effective, practical and inexpensive way to save lives and save billions in taxpayer-paid healthcare costs. Yet less than 50 percent of those thought eligible to take daily aspirin appear to be doing it. Why?

As a cancer prevention researcher I think a lot about people’s health-related behaviors – and how to change them. What if increasing people’s usage of daily aspirin were as simple as changing the packaging? Now, the only way to buy aspirin is in a bottle, making it hard to remember if you took one each day. What if we put it in a calendar blister pack? What if we made the pills in the shape of a heart to remind you why you are taking it? What if the packaging and marketing encouraged you to bring up aspirin at your next doctor’s visit?

I recently submitted these ideas as part of the Target Simplicity Challenge – a pioneering “crowdsourcing” effort led by Target to identify new ideas for simplifying healthcare. I found out about the challenge on Twitter (thanks, @seattlemamadoc!), typed it up and even shot some video on my iPhone. The judging panel of doctors, designers, marketing executives and other industry experts liked it enough to make it one of eight finalists in the competition. This week I’m off to Target headquarters in Minneapolis to talk more about the idea before the winners are announced later in the month. The grand prizes include the opportunity to work with Target on turning my idea into reality.

And the public got a say, too – as you can read about on Target’s site.

We need to stop and think about the easiest and simplest ways possible for people to take advantage of existing scientific evidence that will make them healthier. Doctors and medical researchers should work together with experts in design and marketing to identify more evidence-based opportunities to make prevention and healthcare simpler.

Aspirin is inexpensive and available widely over the counter, but still, we could make it easier to take for those people who could benefit. Short of legislating aspirin counseling (a good idea opined in the New York Times), we need fresh and exciting approaches. I really think better design will increase the appeal of daily aspirin for chronic disease prevention and hope I have the chance to find out.

Christina Clarke, PhD, MPH, is a research scientist at the Cancer Prevention Institute of California (CPIC) and a member of the Stanford Cancer Institute. Part of the Stanford Cancer Institute, the Cancer Prevention Institute of California conducts population-based research to prevent cancer and reduce its burden where it cannot yet be prevented.

Previously: Another big step toward building a better aspirin tablet and New research shows aspirin may cut melanoma risk
Photo by brxO

Cancer, Public Health, Women's Health

Gel polish: What risks lie beneath painted beauty?

Gel polish: What risks lie beneath painted beauty?

nail uvThe desire for beautiful nails has fueled an entire industry of nail salons and inspired new trends in nail care. In my work with the Cancer Prevention Institute of California and the California Healthy Nail Salon Collaborative, I have studied and talked at length about the dangers posed by substances used at nail salons.

Gel polish is the current rage, supposedly offering the long wear of acrylic nails without the accompanying nail damage. Gel polishes are popular because the coating is thinner and looks more natural, there’s no dry-time or smudging, and the nails stay shiny and chip-resistant for weeks. This seems like the ultimate nail dream for salon-goers.

If this sounds almost too good to be true, though, it may be – because this latest beauty treatment carries with it a number of potential health risks.

First, these “no-chip” nails are actually a form of artificial nails, so the same chemicals used in acrylic nails are also used in gel polishes. Of great concern are the acrylates, which are individual chemical molecules (or monomers) that bind together (in a process called polymerization) to form plastic materials. Acrylates can cause allergic and irritant reactions. Contact dermatitis, which includes skin itching, burning, scaling, hives, blistering, and even eczema, has been shown to be associated with these compounds in salon workers as well as salon customers. So if customers and salon workers have had problems with acrylic nails, they will also have problems with gel polishes.

Second, the gel process involves applying pre-mixed gel acrylic to the natural nails, followed by curing the nails under UV light after each coat. The acrylic polymer is crosslinked by the action of the UV light. There are about three separate coats of gel, with each coat followed by 2-3 minutes of curing under the UV light.

UV light is a known human carcinogen, with skin cancer being the biggest concern. Dermatologists have cautioned against the regular use of gel polishes due to UV light exposure, however low.

One research study downplayed the risk of the low exposure, with the investigators stating “that a salon client would need approximately 250 years of weekly manicures that involve the use of UV nail lights to develop the same risk of exposure as just one round of phototherapy sessions.” This comparison of UV light used in nail salons to phototherapy devices such as those used in tanning beds, however, doesn’t take into account the fact that UV light is used with chemicals in gel polishes. There has yet to be research about what the health effects may be when harmful chemicals are used in conjunction with the UV light used in nail salons, so it would be contributing to a false sense of consumer security to make these types of direct comparisons. The jury is definitely still out on the safety of gel polishes with respect to cancer risks.

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Cancer, Genetics, Stanford News

Door dings and DNA – connecting behavior and the environment to your health

Sitting most of the day? Eating poorly? Not sleeping well? Stressed out? These behaviors could be affecting your health—and your DNA.

Think of your body like a car. Sometimes you drive too fast, scrape against a curb or neglect to change your oil at the scheduled time. This behavior may result in minor cosmetic or mechanical “dings” to your car. The environment you drive in, including harsh weather, pothole-littered roads and crowded parking lots may, through no fault of your own, also result in damage to your car. Think about it: How many behaviorally or environmentally caused dings does your car have?

Now, can your environment and behaviors cause analogous dings to your DNA that alter your cancer risk? You are born with your DNA, so it is not something you can change, but you may be able to modify it in important ways. Research shows that through your behavior and environment, your DNA collects imperfections, some of which you may be able to repair through healthy behavior.

In more scientific language, there are epigenetic modifications that do not change the DNA sequence but are layered on top and alter gene expression and protein levels to produce positive and negative impacts on your health. Harmful protein levels may be the result of these dings to your DNA: added negatively acting epigenetic modifications or removed beneficial ones. Protein levels are important, as too much of some or too little of others may cause cells to behave improperly. These imbalances and subsequent cellular behaviors are something researchers are exploring as possible causes for cancer and a variety of other diseases.

Some of your epigenetic modifications (good and bad) may be inherited and perhaps this is part of the reason why cancer, heart disease and Alzheimer’s often run in certain families. As you can imagine, there is great interest in whether and exactly how environment or lifestyle choices such as diet, exercise, sleep and stress levels impact our disease risk. High-fat diets, for example, are fairly consistently associated with cancer, and often with more aggressive cases. Evidence exists suggesting that certain fat by-products impact protein expression in specific pathways related to cancer development. It is possible that high-fat diets epigenetically alter your DNA in a negative fashion leading to cancer – the “you are what you eat” adage may be more prophetic than we thought.

The good news is that just as you can take your car in to get some of the dings cleaned up, you can likely alter your DNA in positive ways through good epigenetic modifications. It may be possible, for example, to exercise regularly or eat certain foods and mitigate some inherited or lifetime-incurred epigenetic modifications. For those of us interested in gene-environment interactions, this is an opportunity to explore how lifestyles and environments modify health through molecular-level DNA alterations. Understanding which of these “dings” cause disease and how we can reduce them will allow us to connect behaviors and environment to their biological manifestations and ultimately reduce disease risk.

Ingrid Oakley-Girvan, PhD, MPH, is a research scientist at the Cancer Prevention Institute of California and a member of the Stanford Cancer Institute. Watch Ingrid’s video on Door Dings and DNA here.

Cancer, Research, Stanford News

Apple- or pear-shaped: Which is better for cancer prevention?

We always want what we don’t have. My teenage daughter is tall and beautiful (in my naturally biased and loving view). But she’s always complaining about her thighs. She thinks they’re too big and don’t look good in skinny jeans. What I see is a young girl with a fresh face, beautiful curves and a youthful spring of energy.

As a molecular epidemiologist, I see one more thing. She has a so-called “pear-shaped” body, which means she has larger thighs relative to a smaller waist, with most of her fat deposited in the lower body. In contrast, people who have “apple-shaped” bodies are heavier in the middle and have their body fat accumulated around the waist, closer to the heart, putting them at a higher risk for abdominal obesity. Many studies have shown that abdominal obesity has a more detrimental effect than overall obesity (as measured by body mass index, the metric calculated using height and weight) on a number of diseases, including type II diabetes, cardiovascular disease and certain cancers (such as those of the breast, ovary, gallbladder and kidney). The specific biological mechanisms are not entirely clear, but we do know from recent research that fat (adipose tissue) is an endocrine organ that actively secretes a variety of chemicals, such leptin, adiponectin, estrogen and other hormones, and inflammatory cytokines. These markers have been linked to growth and proliferation of cancer cells.

The Stanford Cancer Institute and its affiliated research partner, the Cancer Prevention Institute of California (CPIC), currently are conducting studies to understand more clearly the molecular mechanisms underlying the adverse effects of abdominal obesity on cancers. A better understanding of how leptin and inflammatory markers associated with abdominal obesity can influence cancer risk at the molecular level will help clarify the specific steps involved in carcinogenesis, which in turn can aid the development of effective preventive strategies to stop or slow down cancer development.

Our genetic makeup determines largely which body type we are born with, pear or apple. But our eating habits, physical activity and weight management can also affect fat distribution and disease susceptibility. Regular exercise (three times a week) helps increase muscle mass, which in turn can enhance metabolism and lower the risk of metabolism-related conditions, including certain cancers. Whether cancer prevention and weight reduction guidelines differ for those with different body types is another important topic for future studies.

My daughter is the apple of my eye. But I’m glad that, unlike me, she’s a pear. She inherited her father’s body type. In theory, her risk of certain hormone-related cancers or metabolic disorders is lower than mine. So next time she complains about her thighs, I’ll share with her my recent work on abdominal obesity and cancer and try to convince her that she’s lucky to have “big” thighs.

Ann Hsing, PhD, MPH, is director of research for the Cancer Prevention Institute of California (CPIC). Part of the Stanford Cancer Institute, the CPIC conducts population-based research to prevent cancer and reduce its burden where it cannot yet be prevented.

Photo by KDL Designs

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