Leptin could be another relevant indicator of breast cancer risk

Measuring a woman’s leptin levels may offer an additional indicator of her risk of developing breast cancer, say researchers at The University of Texas M. D. Anderson Cancer Center. Their small study, published in the Proceedings for the 2003 Annual Meeting of the American Association for Cancer Research, suggests that because a woman’s production of leptin may reveal her history of eating dietary fat, reading leptin levels may offer more prognostic information than just measuring body mass index and the amount of fat she currently eats.

From the M. D. Anderson Cancer Center:
Leptin could be another relevant indicator of breast cancer risk

TORONTO – Measuring a woman’s leptin levels may offer an additional indicator of her risk of developing breast cancer, say researchers at The University of Texas M. D. Anderson Cancer Center.

Their small study, published in the Proceedings for the 2003 Annual Meeting of the American Association for Cancer Research, suggests that because a woman’s production of leptin may reveal her history of eating dietary fat, reading leptin levels may offer more prognostic information than just measuring body mass index and the amount of fat she currently eats.

And because increased fat is associated with increased bioavailable estrogen and breast cancer risk, “measuring leptin could be an additional marker for assessing breast cancer risk,” says the lead author, Richard Hajek, Ph.D., an instructor at M. D. Anderson’s Center for Research on Minority Health.

“None of these measures are perfect, but the amount of leptin found in a woman’s blood stream can indicate her accumulation of fat over the years,” he says. “Measuring current body weight and fat intake doesn’t offer that kind of perspective.”

Leptin is a hormone produced by fat tissue that signals to the brain when it is time to stop eating. Simply put, researchers say that, ideally, as body fat increases, more leptin is produced, which acts to reduce food intake, and the converse is true – as body fat decreases, less leptin is produced, which stimulates food intake.

But leptin levels also can change according to a pattern of eating, says Hajek. For example, a thin woman with a low leptin level who binges on fatty hamburgers for weeks or months, with a corresponding increase in body fat, will produce a higher level of leptin. If she goes back to eating normally, her leptin level will fall but it may not return as low as it was before the high fat meals. So while her body fat is relatively low, and her current fat intake is also low, her leptin level may reveal evidence of that binge dietary behavior change as well as the extra estrogen, and associated increased risk of developing breast cancer, produced during that bout.

In the research, researchers studied a group of 38 postmenopausal Hispanic women to see how leptin levels fluctuated between women who switched to a high-fiber, low-fat diet and women who switched to high-fiber with no modification in their fat intake. They found that, if body weight and body fat together were not considered, there was a correlation between leptin and the diet. As women ate fewer fat grams, their leptin levels decreased.

But many of the patients were overweight, so their leptin levels were high at the beginning of the study. Despite these different beginning low or high leptin levels, the volunteers who ate more fiber and less fat reduced their levels of leptin and some shed a few pounds. Therefore, leptin levels in these women potentially revealed their lifetime history of eating fat, whereas an examination of their current diet as well as possibly their new weight or body fat composition would only offer a “snapshot” picture, taken just at that point in time.

Thus, when determining the breast cancer risk that a woman has accumulated from eating fat over her lifetime, leptin, body fat composition, and bioavailable estrogen together may offer a more precise indicator, Hajek says.

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Contact: Laura Sussman or Julie Penne, 713-792-0655

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