AICR's Cancer Research Update

Issue 52 — September 22, 2010

Also in this issue:

  1. In Brief: Americans Eating Fewer Fruits and Veggies
  2. Healthy Habits Add Up to Longer Life
  3. Alcohol Links with Breast Cancer Recurrence
  4. Blueberries for Added Insulin Response

Scientist in the Spotlight: Ania K. Majewska

Ania K. MajewskaA growing body of research now suggests coffee has no effect or may even lower the risk of some cancers. Now, in an AICR-funded study, neuroscientist Ania K. Majewska is exploring how caffeine may even fight metastasis to the brain.

Research involving coffee and cancer began in earnest in the early 1980s and today, the view of both coffee and caffeine on cancer risk generally point in the same direction: For the majority of cancers, research suggests that coffee and/or caffeine has no effect on cancer risk. And for a few cancers, it may reduce the risk.

In population studies, the strongest evidence with coffee shows it has no effect on cancer risk. AICR’s 2007 expert report judged coffee unlikely to have any effect on the risk of pan­creatic or kidney cancer – the two cancers for which there was enough evidence to make a conclusion. The evidence was strong enough, the report notes, that its findings are unlikely to change in the foreseeable future.

Caffeine: Fighting Brain Metastasis?

Coffee contains several compounds that have known antioxidant and anti-inflammatory properties, such as cafestol and caffeic acid. Coffee is also a potent source of caffeine, a compound that passes through the blood-brain barrier and affects the brain’s nerve cells, its neurons.

In a novel AICR-funded animal study, Ania K. Majewska, PhD, Assistant Professor in the Department of Neurobiology and Anatomy at the University of Rochester, wanted to investigate if caffeine can slow or prevent breast tumor metastasis to the brain, a com­mon site of metastasis and one of the most challenging areas to treat.

“There are studies that show caffeine affects breast tumors, the front end of the metastasis, but what happens when the tumors go to a target organ, such as the brain?” said Majewska. “No one has looked at it from that side before but we know caffeine affects brain activity.”

In laboratory research, Majewska, a neuroscientist, teamed up with a specialist in breast tumor biology to test various stimulants on breast tumor metastasis to the brain. When they tested caffeine, there were indications it reduced the number of metastatic brain tumors, said Majewska. “Now we’re trying to nail down what it’s changing in the brain.”

“There are studies that show caffeine affects breast tumors, the front end of the metastasis, but what happens when the tumors go to a target organ, such as the brain?”

Majewska believes the changes relate to neurons’ extracellular matrix, the biological scaffolding between cells that is increasingly being found to play an integral role in tumor development. Caffeine’s effect as a stimulant changes the signals neurons send to one an­other at the synapse. Majewska hypothesizes those signals alter the extracellular matrix into an environment that inhibits breast tumor cells from entering the brain, moving about, and/or growing into a tumor.

This study is preliminary, notes Majewska, but it opens an exciting area of research. The brain’s extracellular matrix is poorly under­stood compared to other organs, and “a lot of my work shows that the brain’s extracellular matrix alters brain activity… there’s just a ton to learn.”

With your gernerous support, AICR funds reserach in diet, physical activity and weight management. Please donate now.The Coffee Caveats

With the positive – or non-harmful – news relating coffee/caffeine to cancer, it’s impor­tant to note some studies link consumption to increased risk. For example, limited research has suggested that high intake of coffee might increase risk of bladder cancer and in pregnant women, high intake might increase the chances of childhood leukemia in the child.

The majority of the studies involve moderate amounts of coffee, such as two to four cups. Caffeine is not recommended for everyone. For those who enjoy coffee, moderation is key.

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Mixed Raw FruitIn Brief

Americans Eating Fewer Fruits and Veggies

The evidence is clear that fruits and vegetables play a role in good health – and cancer prevention – but American’s still aren’t biting. Less than one-third of adults are eating the recommended amount of fruits and about one quarter are eating the recommended portion of vegetables, according to a recent report from the Centers for Disease Control and Prevention.

The report data from 2009 showed that only 32% of adults were eating at least two fruits each day, a significant decline from the 2000 data. In 2009, 26 percent of adults consumed three servings or more of vegetables daily, which was about the same as in 2000.

The CDC report analyzed data from the Behavioral Risk Factor Surveillance System for each state. Only one state had statistically significant, although slight, increases in the percentages of adults meeting both the fruit and vegetable target (Idaho). See your state’s fruit and vegetable consumption over the years.

Research Roundup

Older 21Man Teeing OffHealthy Habits Add Up to Longer Life

Eating fruits and vegetables is good for your health. Add exercise and it’s even better. Combine a healthy weight to the mix and the risk of an early death continues to decrease, suggests a large new study that reinforces the impact of lifestyle patterns to mortality.

The study, published in PLoS Medicine, used data from approximately 71,000 Chinese women who are part of the Shanghai Women’s Healthy Study. The women never smoked or drank alcohol regularly. Researchers assigned one point for each of five health factors: being a normal weight; lower waist-hip ratio (an estimate of abdominal fat); regular exercise; never exposed to spouse’s smoking; and relatively high fruit and vegetable daily intake. Scores ranged from 0 points (having no health factors) to 5 points (having all health factors).

After an average of 9 years, researchers found that the higher the healthy lifestyle score, the lower the risk of death from all causes, as well as from cardiovascular diseases and cancer, specifically. This finding held true regardless of whether the women started out with a disease.

Women with 4 to 5 healthy lifestyle factors had a 43 percent lower risk of death overall during the course of the study compared to women with a score of zero: Specifically, heart disease mortality was reduced by 71 percent and cancer mortality by 24 percent.

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Alcohol Links with Breast Cancer Recurrence

Young Female SurvivorBreast cancer survivors who drink three or more alcoholic drinks per week may increase their risk of recurrence, particularly among post menopausal and overweight women, according to a new study published in the Journal of Clinical Oncology.

The study included almost 2,000 women diagnosed with early-stage breast cancer between 1997 and 2000. Women were asked their alcohol consumption at the beginning of the study and tracked an average of 7.4 years.

After analysis, the study found that women who drank over 6 grams/day of alcohol – about three to four drinks per week – had increased risk of recurrence and death due to breast cancer, compared to women who did not drink alcohol. The greater the alcohol intake, the increased risk of recurrence. When separated by selected features, the risk of recurrence was greater among postmenopausal, overweight, and obese women. No associations were found for women at a healthy weight.

The findings are consistent with alcohol's role in increasing the risk of primary breast cancer. AICR’s expert report found that any amount of alcohol increases a women’s risk of breast cancer.

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Blueberries for Added Insulin Response

Blueberries On BushBlueberries may help obese non-diabetic men and women improve insulin sensitivity, making cells more responsive to insulin, suggests a new study that may also provide insights into cancer development. Insulin resistance, a precursor for type 2 diabetes, is also common to many diabetes-related cancers.

The study, published in The Journal of Nutrition, randomly split 32 obese adults into two groups. Twice daily for six weeks, participants drank a smoothie. For one group, each smoothie contained 22.5 grams of freeze-dried whole-blueberry powder – about one cup of fresh blueberries; the second group drank a placebo smoothie that did not contain blueberries. The smoothies appeared identical and participants, along with the scientists, did not know which smoothie they were drinking. Participants were asked to keep all other dietary and physical activity habits the same, including calorie intake.

At the end of the study, 67 percent of people who drank the blueberry smoothie experienced a 10 percent or greater improvement in their insulin sensitivity, compared with 41 percent of people in the placebo smoothie group. The blueberry-smoothie drinkers also experienced a greater change in insulin sensitivity. There were no changes in markers of inflammation; another shared risk factor for diabetes and cancer. The results are not conclusive, note the authors, but they suggest the need for longer studies.

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