P5-01-09: Differences in Serum Estradiol and Prolactin Concentrations in Women Who Yield Nipple Aspiration Fluid and Those Who Do Not.
Authors: Khan SA , Fought AJ , Scholtens DM , McGathey C , Heinz RE , Chatterton RT 
Published: June 2012

Introduction: Nipple aspiration fluid, NAF is an important biosample for breast cancer research, but its utility is limited by the fact that the fraction of NAF-yielders varies from 35% to 90% in various studies. NAF yielders (Y) and non-yielders (NY) are known to differ in demographic characteristics, but the systemic endocrine profiles of Y and NY populations have not been studied, and may affect the generalizability of findings in studies of NAF.

Methods: A subset of participants from an ongoing case-control study was included (120 cases, 120 controls). Cases are women presenting to the Lynn Sage Breast Center with newly diagnosed unilateral breast cancer, and controls are women presenting to the Lynn Sage Mammography Center who do not have cancer. NAF collection was attempted on all consented subjects; those yielding ≥2 uL NAF were designated as Y and those yielding &lt;2 uL NAF were NY (120 Ys, 120 NYs). Menopausal status, age, race, menstrual cycle phase, mammographic density, and serum hormone levels were also collected. Differences between Y and NY groups were tested using a t-test for age, χ2 for race, and Wilcoxon Sum Rank Test for serum hormone levels. Mammographic density was quantitated using digital or digitized images and the CUMULUS software. Linear regression was used to test the relationship between a logged serum hormone values and if a patient yielded adjusting for phase of menstrual cycle in premenopausal women.

Results: Mean ages of Ys and NYs were not different 51.0 and 52.6, respectively (p=0.11). The distribution of Ys by race (Caucasian, African American, other), was not different (χ2 p=0.58). Median serum prolactin concentrations were higher in Ys than NYs for both pre- (7.0 and 2.5 ng/ml) and post-menopausal (5.6 and 2.4 ng/ml) women, respectively (both p&lt;0.01). Median serum estradiol was lower in yielding premenopausal patients only (pre- 90.5 and 64.3 pg/ml p=0.02; post- p=0.59). Stratifying the premenopausal women further into cases and controls, the difference only held for cases and not for controls (p=0.02, p=.033). In the premenopausal patients the regression models suggested that these relationships for estradiol and prolactin remain even after adjusting for phase of the menstrual cycle. No differences in Ys versus NYs were found for progesterone, follicle stimulating hormone, or sex hormone binding globulin. Mammographic density was not different for Ys as compared to NYs for pre- (22% and 20%, p=0.83), but was marginally lower for post-menopausal Ys versus NYs (11% and 15% density; p=0.07). Following stratification of the postmenopausal women into cases and controls, the cases who yielded had significantly lower than NYs (11% and 19% density, p=0.03), but the control Ys and NYs were not different (10% and 11% density, p=0.65).

Conclusion: Pre- and post-menopausal women who yield NAF display increased serum prolactin levels, whereas decreased estradiol levels were observed in premenopausal NAF Ys. These findings suggest that NAF yield has systemic endocrine determinants, with implications for biomarker research on NAF samples. Further characterization of Y and NY women is important, along with standardization of methods of NAF collection, since NAF yield varies widely between studies.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-09.