Issue 5: July 16, 2008
In the News Roundup:
Before Rebecca Cleveland, Ph.D., became a Marilyn Gentry Fellow in Nutrition and Cancer, she was one of the epidemiologists adding to a growing body of evidence linking breast cancer and obesity. Now in her second year as a fellow at the University of North Carolina at Chapel Hill, Dr. Cleveland’s cutting-edge research is helping us understand the role of obesity and related risk factors in breast cancer prevention and survival.
Q: You’ve worked in this area throughout your masters and post-doc. How did you become interested in this field?
A: I started out doing genetic work when I was a grad student, looking at genes related to weight and I was working with breast cancer. I have always been interested in obesity and physical activity as risk factors. My body of work has mostly been in breast cancer and obesity and related pathways.
Q: How has the fellowship helped your research?
A: It’s a tremendous opportunity to come into an assistant professorship and have funding like this. I have some protected time to develop my research interests, generate data, and write grants. Also, having weekly meetings with Dr. Stevens [June Stevens, Ph.D., is UNC’s chair of the Department of Nutrition and Dr. Cleveland’s mentor] – she’s an expert in obesity research – helped me refine my interests in this field. I have done a lot of work on genetic variation in genes with other hormones. Dr. Stevens helped me tie all these things together and take my research one step further in a logical direction, looking at diabetes and how these factors fit in together.
A: We are about to start work on a newly-funded study looking at how diabetes and related factors are associated with breast cancer. I am looking at genes related to insulin-resistance and estrogen, along with insulin-like growth factor 1 and other risk factors.
We are also going to see if breast cancer outcomes are worse for women who have diabetes and/or these risk factors.
Q: How did you decide what genes and other risk factors to study?
A: I had done a lot of background research to find genes associated with breast cancer and obesity and diabetes as well. Our hypothesis is that diabetes is associated with breast cancer risk and reduced survival and that many of the genes associated with hyperinsulinemia [high levels of insulin] are also associated with breast cancer.
Q: You were the lead author in a study that looked at the effect of weight gain on breast cancer survival. What did you find?
A: In the study we looked at pre-diagnostic obesity and weight gain over the lifetime. We followed about 1,500 breast cancer patients. We found that women who were obese at diagnosis, both pre- and postmenopausal breast cancer, had a greater risk of dying from breast cancer overall. For premenopausal women it didn’t seem to make any difference the time period they gained weight, whereas for postmenopausal women it made a difference. When the women gained weight after age 50 they had a two- to three-fold risk of dying. It could be because there are a lot of hormonal changes going on during this time since this is when most women are going through menopause.
Q: How do you see your work making a difference?
A: It’s very satisfying when you can do these studies that have actual clinical impact. The study I did looking at weight gain over the lifetime, now physicians can take this information and put it to use to give patients advice. We’re living in a time right now when obesity is having such an impact on our health and lives. We need to clarify what’s going on: We know this is a problem, but now we need to know why.
For more information on breast cancer – from prevention to detection – AICR offers the brochure Questions and Answers about Breast Health and Breast Cancer.
Night owls, take note. Women who don’t get more than six hours of sleep may be at increased risk of postmenopausal breast cancer, according to new research published in the June issue of Carcinogenesis. The study looked at the reported sleep patterns of approximately 33,000 Chinese women. After tracking the women for up to 11 years, the study found that postmenopausal women who slept nine hours or more had a 33 percent lower risk of breast cancer than those who dozed six or fewer hours. The culprit may be melatonin, a hormone the body naturally produces at night. One theory gaining strength is that lack of sleep disrupts the production of melatonin, which in turn may affect estrogen signaling. This study adds support to the theory: The 9+ sleepers had 42 percent higher levels of melatonin compared to the women who slept less than six hours.
Cancer researchers have long praised the benefits of broccoli. Many laboratory studies have provided clues as to why diets rich in cruciferous vegetables – such as broccoli – may reduce the risk of prostate cancer, along with other cancer types. Now, a study published in PLoS ONE that looked at humans has shown one possible explanation. The study split men into two groups: 13 men added 400 grams of broccoli per week to their meals and 8 men included the same amount of peas in their diet. After six months and one year, researchers measured the expression of prostate related-genes in the men’s prostate tissue. Compared to the pea eaters, the broccoli eaters showed significantly more changes in the expression of genes linked with prostate cancer protection. The major difference was found in men who have the GSTM1 gene, which is carried in about half the population. The scientists showed that the broccoli compound called sulforaphane is involved in changes that may be responsible. The results suggest that even eating small amounts of broccoli may lead to changes in the cell signaling pathway, which can effect gene expression.
For head and neck cancer survivors, shoulder pain and disability are frequent complications. Some steady and incremental resistance exercise may help, according to a Canadian study published in this month’s Cancer. The study randomly assigned 52 head and neck cancer survivors to one of two exercise groups: the standard therapeutic protocol or a resistance exercise therapy that got progressively harder. Exercises in the standard therapy included stretching, light weights, and strength exercise focusing on specific muscle groups. The exercises in the experimental group were similar except for the strength training. In the experimental group, the strength exercises were tailored to individual survivors depending upon their starting ability. Slowly and progressively, the survivors lifted heavier weights targeted for specific muscle groups. All the patients were supervised. At the end of 12 weeks, the survivors in the progressive exercise group reported less pain and disability than survivors in the standard exercise group. The progressive group also showed better muscle strength and endurance. The results strengthen the hypothesis that improved muscle strength and endurance can lessen pain.All active news articles
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