Abstract
While obesity is a known risk factor for postmenopausal breast cancer, the molecular
mechanisms involved are unclear. Systemic levels of leptin, the product of the ob (obesity) gene, are increased in obese individuals (body mass index, BMI, over 25)
and are higher in women than men. Leptin has been found to stimulate the growth of
breast cancer cells in vitro. Our goal was to determine whether leptin was 1) present in nipple aspirate fluid
(NAF), and 2) whether NAF leptin levels were associated with a) levels in serum, b)
obesity, and c) breast cancer. We collected and evaluated NAF specimens from 83 subjects
and serum specimens from 49 subjects. NAF leptin was detectable in 16/41 (39 %) of
premenopausal and 21/42 (50 %) postmenopausal subjects. NAF leptin was significantly
lower (p = 0.042) in premenopausal than postmenopausal women with a BMI < 25, but
not in those with a higher BMI. NAF leptin was significantly associated with BMI in
premenopausal (p = 0.011) but not in postmenopausal women. Serum leptin was associated
with BMI in both premenopausal and postmenopausal women (p = 0.0001 for both). NAF
and serum leptin were associated in premenopausal (p = 0.02) but not postmenopausal
women. Neither NAF nor serum leptin was associated with premenopausal or postmenopausal
breast cancer. Our findings include that 1) leptin is present in the breast and detectable
in a subset of NAF samples, 2) NAF leptin in premenopausal but not postmenopausal
women parallels serum leptin levels, and 3) neither NAF nor serum levels of leptin
were associated with premenopausal or postmenopausal breast cancer.
Key words
Obesity - Premenopause - Postmenopause - Protein concentration - Leptin release
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E. R. Sauter
University of Missouri - Columbia
One Hospital Drive · Rm 588 · Columbia · MO 65212 ·
Phone: +1(573)8824471
Fax: +1(573)8844585
Email: sautere@health.missouri.edu