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Cancer, Health and Fitness, Pediatrics, Public Health, Research, Women's Health

Examining the long-term health benefits for women of exercise in adolescence

Examining the long-term health benefits for women of exercise in adolescence

soccer_8.4.15Sometime around the age of five, I distinctly remember my mother telling me, “You have to play a sport. You can pick any sport you want, but you have to play a sport.” I recall this encounter vividly because I really, really didn’t want to play sports. At the time, I was the “everything-has-to-be-pink, Barbie-doll-playing, glitter-loving” type. But I picked a sport, soccer, and surprisingly stuck with it through college.

Fast forward to today, when I came across new research touting the health benefits of exercise during adolescence and was compelled to send a “Thanks, mom” text for her fitness mandate. The findings, which were recently published in the journal Cancer Epidemiology, Biomarkers & Prevention, show that women who regularly exercised as teenagers had a decreased risk of dying from cancer, cardiovascular disease and other causes during middle-age and later in life.

The study was conducted by Vanderbilt University Medical Center and the Shanghai Cancer Institute and involved the analysis of data from the Shanghai Women’s Health Study, a large ongoing prospective cohort study of 74,941 Chinese women ages 40 to 70.

Researchers defined regular exercise as occurring a minimum of once a week for three consecutive months. Lead author Sarah Nechuta, PhD, said in a release, “In women, adolescent exercise participation, regardless of adult exercise, was associated with reduced risk of cancer and all-cause mortality.”

More details about the study results:

Investigators found that participation in exercise both during adolescence and recently as an adult was significantly associated with a 20 percent reduced risk of death from all causes, 17 percent for cardiovascular disease and 13 percent for cancer.

While there have been several studies of the role of weight gain and obesity on overall mortality later in life, the authors believe this is the first cohort study of the impact of exercise during adolescence on later cause-specific and all-cause mortality among women.

The authors note that an important next step is to evaluate the role of adolescent exercise in the incidence of major chronic diseases, such as cardiovascular disease and major cancers, which will also help provide more insight into the mechanisms of disease.

Previously: Study finds teens who play two sports show notably lower obesity rates, Exercise may lower women’s risk of dementia later in life, How physical activity influences health and Stanford pediatrician discusses developing effective programs to curtail childhood obesity
Photo by Ole Olson

Cancer, Research, Science, Stanford News, Stem Cells

Liver stem cell identified in mice

Liver stem cell identified in mice

Image of liver stem cellsAn elusive quarry has finally been chased to ground. Or, more accurately, to the central vein of one of our most important organs: the liver. Developmental biologist Roel Nusse, PhD, and visiting scholar and gastroenterologist Bruce Wang, MD, announced the identification of the liver stem cell in mice today in Nature. The finding will help researchers better understand liver biology and disease. It may also aid in the decades-long quest to find a reliable and efficient way to grow liver cells, called hepatocytes, in the laboratory for study and to test the effect of drugs.

Until now, researchers had assumed that all hepatocytes were created equal. And none of them seemed to have stem-cell-like traits. As Nusse described in our release:

There’s always been a question as to how the liver replaces dying hepatocytes. Most other tissues have a dedicated population of cells that can divide to make a copy of themselves, which we call self-renewal, and can also give rise to the more-specialized cells that make up that tissue. But there never was any evidence for a stem cell in the liver.

Wang and Nusse took a different approach. They looked in the liver to see which cells, if any, were expressing a gene called Axin2. Axin2 is expressed when a cell encounters a member of the Wnt protein family. Years of previous work in the Nusse lab have shown that Wnt family members are critical regulators of embryonic development and stem cell maintenance.

They found a small population of Axin2-expressing hepatocytes with just two copies of each chromosome surrounding the central vein of the liver. These cells can both self-renew and divide to create new hepatocytes that migrate outward from the vein. As they migrate, these cells become polyploid and begin to express hepatocyte-specific genes. Eventually much of the animals’ livers were made up of these stem-cell descendents. As Wang described:

People in the field have always thought of hepatocytes as a single cell type. And yet the cell we identified is clearly different from others in the liver. Maybe we should accept that there may be several subtypes of hepatocytes, potentially with different functions.

If this result in mice is also found to be true in humans, it’s possible that the liver stem cells may be easier to grow in the laboratory that normal hepatocytes. This would enable researchers to test the effect of drugs under development on human liver cells before they are tested in people (my colleague Bruce Goldman wrote about another potential solution to this problem last year). As Wang explained:

The most common reason that promising new drugs for any type of condition fail is that they are found to be toxic to liver. Researchers have been trying for decades to find a way to maintain hepatocytes in the laboratory on which to test the effects of potential medications before trying them in humans. Perhaps we haven’t been culturing the right subtype. These stem cells might be more likely to fare well in culture.

The finding opens the doors to answering other important questions as well, said Wang: “Does liver cancer arise from a specific subtype of cells? This model also gives us a way to understand how chromosome number is controlled. Does the presence of the Wnt proteins keep the stem cells in a diploid state? These are fundamental biological questions we can now begin to address.”

Previously: Which way is up? Stem cells take cues from localized signals, say Stanford scientists and The best toxicology lab: a mouse with a human liver
Photo of liver stem cells (red) and their progeny (green) by Bruce Wang

Cancer, Chronic Disease, Dermatology, Stanford News, Surgery, Transplants

Rebuilding Cassie’s smile: A lung transplant patient’s struggle with skin cancer

lung patientWhen I first met Cassie Stockton, she was seated in an exam chair in Stanford’s dermatology clinic, getting cosmetic skin treatments. Lovely and young, just 21 years old, it seemed a bit silly. How could she possibly need injectable lip fillers or laser skin treatments?

I knew Stockton had a lung transplant at 15 and that the immunosuppressant drugs she was required to take to keep her body from rejecting the donated lungs had made her susceptible to skin cancer. But it wasn’t until I researched her story in depth that I truly understood how she ended up needing regular cosmetic treatments here.

As I explain in my recently published Stanford Medicine article, her story began at birth:

Born premature, [Cassie] was intubated the first two weeks of life, then sent home with her mother and an oxygen tank. She remained on oxygen 24 hours a day for the first two years of her life. Eventually, she was diagnosed with bronchopulmonary dysplasia, a chronic lung disorder …

Sixteen years later, the donated gift of new lungs saved her life – but it left scars, both emotional and physical:

The day Stockton woke up out of the anesthesia six years ago after a 13-hour surgery at the Transplant Center at Lucile Packard Children’s Hospital Stanford, she breathed in oxygen with newly transplanted lungs, and breathed out sobs. Tears streamed down her face. “At first, I thought she was in pain,” says her mother, Jennifer Scott, who stood by her side. But that wasn’t it. Stockton was overwhelmingly sad because she now knew her new lungs were the gift of a child. It was Dec. 6, 2009, just before Christmas. The death of someone else’s child had given her a whole new life.

And now:

Every four months, she and her fiancé make the four-hour drive from their home in Bakersfield, California, past the oil rigs and cattle farms to Stanford’s Redwood City-based dermatology clinic for her skin cancer screening. It’s been two years of treatments: freezings, laserings, a total of eight outpatient skin surgeries — the most significant resulting in the removal of the left half of her lower lip. The dermatologic surgeon removes the skin cancers, and then gets to work to repair the damage. “It’s heart-breaking to have to remove the lip of a 21-year-old woman,” says Tyler Hollmig, MD, clinical assistant professor of dermatology and director of the Stanford Laser and Aesthetic Dermatology Clinic, who leads Stockton’s treatment and keeps her looking like the young woman she is, restoring her skin, rebuilding her lip, making sure she keeps her smile.

Stockton doesn’t complain about any of the struggles she’s had post transplant. She knows she got a second chance at life. And, she tells me, it’s her job to take care of the lungs given to her by that child who died.

Previously: This summer’s Stanford Medicine magazine shows some skin
Photo by Max Aguilera-Hellweg

Cancer, Genetics, Women's Health

Genetic testing and its role in women’s health and cancer screening

Genetic testing and its role in women's health and cancer screening

14342954637_3f8c3fde77_zYears ago, when I first learned that genetic testing could help screen for some cancers, such as breast, ovarian and bone, it seemed like a no-brainer to get this testing done. Now I know better; genetic testing is a helpful tool that can help you assess your risk for certain kinds of cancer, but it’s not recommended for everyone. Senior genetic counselor Kerry Kingham, a clinical assistant professor affiliated with the Cancer Genetics Clinic at Stanford, explains why this is the case in a recent Q&A with BeWell@Stanford.

Cancer can be “hereditary” or “sporadic” in nature, Kingham says. Hereditary cancers, such as the forms of breast cancer related to a mutation in the BRCA1 or BRCA2 genes, are associated with an inherited genetic mutation. In contrast, sporadic cancers arise independent of family history or other risk factors. Since genetics testing detects gene mutations, it can only be used to help screen for the mutations that may lead to forms of hereditary cancer.

Kingham elaborates on this point, when it makes sense to get genetic testing, and what the results may mean in the Q&A:

Twelve percent of women in the U.S. develop breast cancer; it is a common disease. Yet, only five to ten percent of these women will develop breast cancer because of a hereditary gene mutation.

The best step to take prior to deciding whether or not to proceed with genetic testing is to meet with a genetic counselor. Your doctor can provide a referral. The genetic counselor will take a three generation family history, discuss the testing that might be indicated for you or a family member, and explain the risks and benefits of the testing. They also discuss the potential outcomes of the testing: whether a mutation is found, a mutation is not found, or there are uncertain results. Even when a genetic test is negative, this may not mean that the individual or their family is not at risk for cancer.

At this point you may be wondering: Why bother with genetic testing if it’s only useful for hereditary cancers and a negative test result is no guarantee you’re risk-free? Kingham’s closing comment addresses this question nicely: “I would say that your genes don’t change – they are what they are, and knowing what is in our genes can often help us learn how to take better care of our health.”

Previously: Stanford researchers suss out cancer mutations in genome’s dark spotsAngelina Jolie Pitt’s New York Times essay praised by Stanford cancer expertNIH Director highlights Stanford research on breast cancer surgery choices and Researchers take a step towards understanding the genetics behind breast cancer
Photo by Paolo

Cancer, Genetics, Research, Science, Stanford News

Using CRISPR to investigate pancreatic cancer

Using CRISPR to investigate pancreatic cancer

dna-154743_1280Writing about pancreatic cancer always gives me a pang. My grandmother died from the disease over 30 years ago, but I still remember the anguish of her diagnosis and the years of chemotherapy and surgery she endured before her death. This disease is much more personal to me than many I cover.

Unfortunately, survival rates haven’t really budged since I was in high school, in part because the disease is often not diagnosed until it’s well established. As geneticist  Monte Winslow, PhD, described to me in an email:

Pancreatic cancer is very common and almost uniformly fatal. Human pancreatic cancers usually have many mutations in many different genes but we know very little about how most of them drive pancreatic cancer initiation, development, and progression. Recreating these cancer-causing mutations in cells of the mouse pancreas can generate tumors that look and behave very similarly to human pancreas cancer.

Unfortunately, traditional methods used to generate mouse models of human cancer are very time-consuming and costly.

Winslow, along with postdoctoral scholar Shin-Heng Chiou, PhD, and graduate student Ian Winters, turned to the latest darling of the biochemistry world — the gene-editing system known as CRISPR — to devise a way to quickly and efficiently turn off genes implicated in the development of pancreatic cancer in laboratory mice. Their work will be featured on the cover of Genes and Development on Monday. As Winslow described:

Our goal was use CRISPR/Cas9 genome editing to make altering a gene of interest in pancreas cancer simple and fast. Shin-Heng and Ian worked together to develop novel tools and bring them together to generate this new system that we hope will dramatically accelerate our understanding of pancreas cancer. The increased basic understanding of how this cancer works may ultimately lead to better therapies for patients.

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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

Big data, Cancer, Genetics, Immunology, Research, Science, Stanford News

Linking cancer gene expression with survival rates, Stanford researchers bring “big data” into the clinic

Linking cancer gene expression with survival rates, Stanford researchers bring "big data" into the clinic

Magic 8 ball“What’s my prognosis?” is a question that’s likely on the mind, and lips, of nearly every person newly diagnosed with any form of cancer. But, with a few exceptions, there’s still not a good way for clinicians to answer. Every tumor is highly individual, and it’s difficult to identify anything more than general trends with regard to the type and stage of the tumor.

Now, hematologist and oncologist Ash Alizadeh, MD, PhD; radiologist Sylvia Plevritis, PhD; postdoctoral scholar Aaron Newman, PhD; and senior research scientist Andrew Gentles, PhD, have created a database that links the gene-expression patterns of individual cancers of 39 types with the survival data of the more than 18,000 patients from whom they were isolated. The researchers hope that the resource, which they’ve termed PRECOG, for “prediction of cancer outcomes from genomic profiles” will provide a better understanding of why some cancer patients do well, and some do poorly. Their research was published today in Nature Medicine.

As I describe in our release:

Researchers have tried for years to identify specific patterns of gene expression in cancerous tumors that differ from those in normal tissue. By doing so, it may be possible to learn what has gone wrong in the cancer cells, and give ideas as to how best to block the cells’ destructive growth. But the extreme variability among individual patients and tumors has made the process difficult, even when focused on particular cancer types.

Instead, the researchers pulled back and sought patterns that might become clear only when many types of cancers, and thousands of patients were lumped together for study:

Gentles and Alizadeh first collected publicly available data on gene expression patterns of many types of cancers. They then painstakingly matched the gene expression profiles with clinical information about the patients, including their age, disease status and how long they survived after diagnosis. Together with Newman, they combined the studies into a final database.

“We wanted to be able to connect gene expression data with patient outcome for thousands of people at once,” said Alizadeh. “Then we could ask what we could learn more broadly.”

The researchers found that they were able to identify key molecular pathways that could stratify survival across many cancer types:

In particular, [they] found that high expression of a gene called FOXM1, which is involved in cell growth, was associated with a poor prognosis across multiple cancers, while the expression of the KLRB1 gene, which modulates the body’s immune response to cancer, seemed to confer a protective effect.

Alizadeh and Plevritis are both members of the Stanford Cancer Institute.

Previously: What is big data?Identifying relapse in lymphoma patients with circulating tumor DNA,  Smoking gun or hit-and-run? How oncogenes make good cells go bad and Big data = big finds: Clinical trial for deadly lung cancer launched by Stanford study
Photo by CRASH:candy

Applied Biotechnology, Big data, Cancer, Genetics, Research, Science, Stanford News

Peeking into the genome of a deadly cancer pinpoints possible new treatment

Peeking into the genome of a deadly cancer pinpoints possible new treatment

small cell lung cancerSmall cell lung cancer is one of the most deadly kinds of cancers. Typically this aggressive disease is diagnosed fairly late in its course, and the survival rates are so dismal that doctors are reluctant to even subject the patient to surgery to remove the tumor for study. As a result, little is known about the molecular causes of this type of cancer, and no new treatments have been approved by the Food and Drug Administration since 1995.

Now a massive collaboration among researchers around the world, including the University of Cologne in Germany and Stanford, has resulted in the collection of more than 100 human small cell lung cancer tumors. Researchers sequenced the genomes of the tumors and identified some key steps in their development. They also found a potential new weak link for treatment.

The findings were published today in Nature, and Stanford cancer researcher Julien Sage, PhD, one of three co-senior authors of the paper, provided some details in an email:

With this larger number of specimens analyzed, a more detailed picture of the mutations that contribute to the development of small cell lung cancer now emerges. These studies confirmed what was suspected before, that loss of function of the two tumor suppressor genes, Rb and p53, is required for tumor initiation. Importantly, these analyses also identified new therapeutic targets.

The researchers also saw that, in about 25 percent of cases, the Notch protein receptor was also mutated. This protein sits on the surface of a cell; when Notch binds, it initiates a cascade of signaling events within the cell to control its development and growth. As Sage explained:

The mutations in the Notch recepetor were indicative of loss of function, suggesting that Notch normally suppresses small cell lung cancer development. Indeed, when graduate student Jing Lim in my lab activated Notch in mice genetically engineered to develop small cell lung cancer, we found a potent suppression of tumor development. These data identify the Notch signaling pathway as a novel therapeutic target in a cancer type for which new therapies are critically needed.

This is not Sage’s first foray into fighting small cell lung cancer. In 2013, he collaborated with other researchers at Stanford, including oncologist Joel Neal, MD, PhD, to identify a class of antidepressants as a possible therapy for the disease.

Previously: Gene-sequencing rare tumors – and what it means for cancer research and treatment, Listening in on the Ras pathway identifies new target for cancer therapy and Big data = big finds: Clinical trial for deadly lung cancer launched by Stanford study
Image by Yale Rosen

Cancer, Clinical Trials, Dermatology, Genetics, Pain, Pediatrics, Research, Stanford News

The worst disease you’ve never heard of: Stanford researchers and patients battle EB

The worst disease you've never heard of: Stanford researchers and patients battle EB

EB patient and docsI’m often humbled by my job. Well, not the job, exactly, but the physicians, researchers, and especially patients who take the time to speak with me about their goals and passions, their triumphs and fears. Their insight helps me as I struggle to interpret what goes on here at the Stanford University School of Medicine for others across the university and even around the world.

But every once in a while, an article comes along that brings me to my (emotional) knees. My article “The Butterfly Effect” in the latest issue of Stanford Medicine magazine describes the toll of a devastating skin disease called epidermoloysis bullosa on two young men and their families, as well as the determined efforts of a dedicated team of doctors and scientists to find a treatment. As a result, Stanford recently launched the world’s first stem-cell based trial aimed at correcting the faulty gene in the skin cells of patients with a severe form of the condition, which is often called EB.

I trace the path of one family as they learn, mere hours after his birth, that their son, Garrett Spaulding, has EB, which compromises the ability of the outer layers of the to stick together during friction or pressure. Patients develop large blisters and open wounds over much of their bodies. It’s incurable, fatal, and nearly indescribably painful. Paul Khavari, MD, PhD, now the chair of Stanford’s Department of Dermatology, was a young doctor at the time newborn Garrett was admitted to Lucile Packard Children’s Hospital Stanford in 1997.

“His whole body, his skin was blistered and falling off everywhere someone had touched him,” Khavari recalls in the article. “His parents were devastated, of course, at a time that was supposed to be one of the most joyful of their lives.”

Garrett’s now 18 years old, but the disease is taking its toll.

You’ll also meet Paul Martinez, one of the first participants in Stanford’s new clinical trial. He’s 32, which makes him an old man in the EB community. Unlike many EB patients, he has finished high school and completed a college degree in business marketing with a dogged determination that makes me ashamed of my petty complaints about my minor life trials. And he’s done it without relying on the pain medications essential for most EB patients. As he explains in the article:

We don’t know what it is like to not be in pain. It’s just normal for us. […] I have a very high tolerance, and don’t take any pain medication. I cherish my mind a lot. Rather than feel like a zombie, I prefer to feel the pain and feel alive.

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Aging, Cancer, Dermatology, Genetics, Research, Stanford News

Genetic secrets of youthful skin

Genetic secrets of youthful skin

new hatEvery year, upwards of $140 billion a year gets spent on cosmetics. In the United States alone, says an authoritative report, a recent year saw upwards of 5.6 million Botox procedures, 1.1 million chemical peels, almost a half-million laser skin procedures, 196,286 eyelid surgeries and a whole bunch of face lifts.

If you’ve got the courage to compare your present-tense face with the one you were wearing 20 or even 10 years ago, you’ll see why. As I wrote in a just-published Stanford Medicine article, “Wither youth?”:

The terrain of aging skin grows all too familiar with the passing years: bags under the eyes, crow’s feet, jowls, tiny tangles of blood vessels, ever more pronounced pores and pits and pigmentation irregularities. Then there are wrinkles — long, deep “frown lines” radiating upward from the inside edges of the eyebrows and “laugh lines” that trace a furrow from our nostrils to the edges of our lips in our 40s, and finer lines that start crisscrossing our faces in our 50s. Sagging skin gets more prominent in our later years as we lose bone and fat.

“And,” I added wistfully, “it’s all right there on the very outside of us, where everyone else can see it.”

Stanford dermatologist Anne Chang, MD, who sees a whole lot of skin, got to wondering: Why does skin grow old? Armed with a sophisticated understanding of genetics, she went beyond lamenting lost youth and resolved to address the question scientifically, asking: “Can you turn back time? Can aging effects be reversed? Can you rejuvenate skin, make it young again?”

The answers she’s come up with so far – from hereditary factors to a possible underlying genetic basis for how some treatments now in common commercial cosmetic use (such as broadband light therapy) could potentially slow or even reverse the aging of skin – are described in my magazine article.

Previously: This summer’s Stanford Medicine magazine shows some skinResearchers identify genetic basis for rosacea, New study: Genes may affect skin youthfulness and Aging research comes of age
Photo by thepeachpeddler

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