Study: Is asparagus linked to breast cancer metastasis?
|At a glance||Questions for your doctor|
This study is about:
Identifying new targets that reduce the ability of breast cancer cells to spread and become .
Why is this study important?
Breast cancer becomes deadly when it metastasizes—cancer cells leave the breast, enter the blood stream and then invade a secondary site such the brain, lungs or other organs. This study suggests that reducing the amount of the amino acid asparagine may be one way to decrease the likelihood of breast cancer becoming .
In mice that were bred to develop breast cancer:
- limiting asparagine by either experimental approaches or diet reduced breast cancer .
- increasing asparagine by either experimental approaches or diet increased breast cancer .
“When the availability of asparagine was reduced, we saw little impact on the primary tumor in the breast [in mice], but tumor cells had reduced capacity for metastases in other parts of the body," said Greg Hannon, lead study author and Cambridge University cancer researcher.
What does this mean for me?
Breast cancer that stays confined to the breast is not deadly. But it is more difficult to treat and can become fatal if it metastasizes—if cancer cells spread beyond the tumor and into other organs in the body. These preliminary study results imply that reducing bodily amounts of asparagine is one way to decrease the risk of breast cancer . This result, however, needs to be confirmed by other studies. In addition, it is important to remember that animal models of breast cancer do not always mimic the disease in humans.
Even if future guidelines were to support a reduction of asparagine to decrease the risk of breast cancer , it is virtually impossible to eliminate the substance from your diet. Foods rich in asparagine include not only asparagus, but also dairy, beef, poultry, eggs, fish, seafood, potatoes, legumes, nuts, seeds, soy and whole grains. Experts agree that you should not drastically change your diet in an attempt to reduce the amount of asparagine you consume. Asparagine is found in all protein rich foods, many of which are considered part of a healthy diet. In addition, your body naturally makes asparagine. If you are concerned about how your diet will affect your outcome consider discussing this with your doctor or a nutritionist.
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Knott, Simon RV, Wegenblast E, et al. “Asparagine bioavailability governs in a model of breast cancer.” Nature. February 15, 2018; Vol. 554:378–381.
FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.
This article is relevant for:
People diagnosed with breast cancer
This article is also relevant for:
people with breast cancer
people with metastatic or advanced cancer
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Preventing or eliminating is an important goal of breast cancer treatment. Mouse models of breast cancer are often used to better understand how breast cancers metastasize and to identify potential targets for treatment that can reduce or eliminate the potential of breast cancer cells.
Asparagine is an amino acid that is a building block for proteins. Found in many foods, it is also made in the body by a cellular enzyme called asparagine synthetase. This study evaluated the effect of asparagine, either in the diet or produced by the naturally occurring enzyme asparagine synthetase, on breast cancer .
Researchers of this study wanted to know:
Which molecules can cause breast cancer cells to metastasize?
Population(s) looked at in the study:
This study used mice models of breast cancer. In addition, researchers looked at levels of asparagine synthetase in breast cancer patients and in a small sample of matched breast tumor and lung samples.
Initially the study authors used sophisticated in vitro (test tube) techniques to identify molecules that may cause . Among the top candidates, asparagine synthetase appeared to play a critical role. The researchers then conducted multiple areas of related mouse study:
- Mice that were predisposed to breast cancer were intravenously injected with special breast cancer cells which had low levels of asparagine synthetase. These cells had reduced levels of asparagine). Control mice were injected with breast tumor cells with normal amounts of asparagine synthetase and asparagine.
- Mice with reduced asparagine synthetase had significantly fewer lung metastases than control mice.
- Fat pads of mice that were predisposed to breast cancer were directly injected with breast cancer cells in which the function of asparagine synthetase was experimentally reduced (thereby reducing the level of asparagine).
- No significant change in the development of primary breast tumors was observed; however, lung was significantly reduced compared to mice in the control group.
- Mice predisposed to breast cancer once breast tumors appeared were treated 5 times per week for 19 days with L-asparaginase, a chemotherapy drug that blocks the production of asparagine and is currently used to treat acute lymphoblastic leukemia, which is known to thrive on asparagine.
- Although no significant difference was detected in the primary tumor, was reduced in mice treated with L-asparaginase compared to controls.
- Mice that were predisposed to develop breast cancer were fed a diet that was either low or high in asparagine.
- Dietary asparagine did not affect the primary tumors, however, mice with a low-asparagine diet had a lower burden than mice with a high-asparagine diet.
Interestingly, when the study authors reviewed records of breast cancer patients (gene expression data from 2 data sets as well as a small number of matched breast tumors and lung metastases), they found that breast tumors with the highest levels of asparagine synthetase were most likely to metastasize, especially to the , brain, liver, and lungs.
It is important to remember that cancer therapies that work well in rodents don’t always translate to humans. While it is possible that dietary intake of asparagine may influence potential of breast cancer in humans, this hypothesis needs to be validated in human studies.
Asparagine is a non-essential amino acid that our bodies naturally synthesize. This new study suggests that decreasing levels of asparagine in mice reduces . If after further study, reduction of asparagine levels proves to reduce the potential of human breast cancer, other methods to reduce cellular availability of asparagine may need to be developed, because regulating dietary levels of asparagine would be extremely difficult, if not impossible.
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Nutrition for people diagnosed with cancer
The National Comprehensive Cancer Network (NCCN) recommends the following for cancer survivors:
- Think about your food choices and amount of fruits, vegetables and unrefined grains you eat compared with red and processed meats, alcohol, and foods or drinks with added fat or sugar.
- Think about your eating habits, including portion size, snacking, how often you eat out and use of added fats or sugars.
- All survivors should be encouraged to:
- Make informed choices about food to ensure variety and adequate nutrient intake.
- Limit refined sugars.
- Eat a diet that is at least 50% plant-based, consisting mostly of vegetables, fruit and whole grains.
- Track calorie intake; monitoring of calories is an effective way to manage weight.
- Minimize alcohol intake to no more than one drink per day for a woman and two drinks per day for a man.
- For patients desiring further dietary guidelines, the USDA approximate food plate volumes are:
- Vegetables and fruits should comprise half the volume of food on the plate
- Vegetables: 30% of plate; Fruits 20% of plate
- Whole grains: 30% of plate
- Protein: 20% of plate
- Recommended sources of nutrients:
- Fat: plant sources such as olive or canola oil, avocados, seeds and nuts, and fatty fish.
- Carbohydrates: fruits, vegetables, whole grains and legumes.
- Protein: poultry, fish, legumes, low-fat dairy foods, and nuts.
The Academy of Nutrition and Dietetics, the United States Office of Disease Prevention and Health Promotion and the American Institute for Cancer Research also publish expert guidelines on nutrition and health.
- Can my diet affect my risk for breast cancer ?
- What should I be eating to maximize my health and ability to tolerate treatment?
- Can you provide me with a referral to a nutritionist?
The following are studies focused on nutrition for people diagnosed with breast cancer.
- NCT05259410: Time Restricted Eating During Chemotherapy for Breast Cancer. This study will look at whether intermittent fasting during treatment will improve treatment related outcomes, patient related outcomes, and limit treatment related weight gain.
- NCT04000880: AMPLIFY: An Online Weight Loss Study Specifically for Cancer Survivors. AMPLIFY is a nation-wide, web-based diet and exercise study recruiting overweight survivors of breast, , ovarian, renal, colorectal, endometrial cancer and multiple myeloma in people age 50 and older who are interested in becoming more active, eating better and losing weight.
- NCT04298086: A Study of the Body's Response to Exercise and a Plant-Based Diet in Overweight Postmenopausal Women With Breast Cancer. This study is looking to find out what effects exercise and a plant-based diet have on aromatase levels in postmenopausal women who are overweight and being treated with an aromatase inhibitor for their HR+ breast cancer.
- NCT04365569 Evaluating the Effectiveness of an Individualized Nutrition and Physical Activity Counseling Program. This pilot study looks at whether a tailored in-person and telephone-based nutrition and exercise counseling program can help breast cancer patients improve weight and fitness and thus improve cancer outcomes.
- NCT03824145: Every Day Counts: A Lifestyle Program for Women With Breast Cancer (EDC). This study will examine diet and activity, body composition, blood and quality of life in breast cancer patients. The study will recruit 176 women with MBC in Milwaukee (n=88) and Chicago (n=88).
The following resources can help you locate a nutritionist near you or via telehealth
- You can find a registered dietician in your area through Eatright.org, the website for the Academy of Nutrition and Dietetics. Search for nutritionists by specialty, including "cancer," "weight management" and "heart health."
- The YMCA has a free program called Livestrong at the YMCA. This program includes a free 12-week membership and fitness training with certified exercise experts. You can search by zip code for a program near you.
Other ways to find experts
- Register for the FORCE Message Boards and post on the Find a Specialist board to connect with other people who share your situation.
- The National Cancer Institute (NCI)-designated comprehensive cancer centers have specialists to manage the symptoms and side effects from cancer prevention or treatment.
Who covered this study?
Spread of breast cancer linked to compound in asparagus and other foods This article rates 4.5 out of 5 stars
Los Angeles Times
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