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Losing weight lowered levels of proteins associated with tumor growth

In Fred Hutch study, obese women who lost weight significantly lowered levels of proteins in the blood that help certain tumors grow

Fred Hutchinson Cancer Research Center

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IMAGE:  "Exercise is important for helping to prevent weight gain, and to maintain weight loss, but does not cause a large amount of weight loss on its own, " said Catherine Duggan,... view more

Credit: Fred Hutch

SEATTLE - Overweight or obese women who lost weight through diet or a combination of diet and exercise also significantly lowered levels of proteins in the blood that help certain tumors grow, according to a Fred Hutchinson Cancer Research Center study published July 14 in Cancer Research, a journal of the American Association for Cancer Research.

Two study leaders - Dr. Catherine Duggan, principal staff scientist in the Public Health Sciences Division, and Dr. Anne McTiernan, cancer prevention researcher in the Public Health Sciences Division and the article's senior author - are available to provide details on the study and its implications.

The study:

  • Measured three proteins that are known to enhance tumor-related angiogenesis - the formation of blood vessels that feed tumors and enable them to grow.

  • Was intended to see how cancer-promoting proteins changed when overweight, sedentary, postmenopausal women lost weight through diet or diet and exercise over the course of a year.

  • Enrolled 439 healthy women (they did not have cancer), placing each participant in one of four study arms:

    • Calorie- and fat-restricted diet.
    • Aerobic exercise five days a week.
    • Combined diet and exercise.
    • Control (no intervention).

  • Found that women in the diet arm and the diet and exercise arm lost more weight and had significantly lower levels of angiogenesis-related proteins, compared with women in the exercise-only arm and the control arm.

The authors said that it is known that being overweight and having a sedentary lifestyle are associated with increased risk for developing certain cancers, but the reasons for this relationship are not clear.

This study shows that weight loss may be a safe and effective way to improve the "angiogenic profile" of healthy individuals, meaning they would have lower blood levels of cancer-promoting proteins. Although the researchers cannot say for certain that this would impact the growth of tumors, they believe there could be an association between reduced protein levels and a less favorable environment for tumor growth.

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The study was funded by the National Cancer Institute and the Breast Cancer Research Foundation. Duggan and McTiernan declare no conflicts of interest.

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