GROSS CYSTIC-DISEASE FLUID PROTEIN IN NIPPLE ASPIRATES OF BREAST FLUID OF ASIAN AND NON-ASIAN WOMEN

Gross cystic disease fluid protein 15 (GCDFP-15) is universally presen t in the apocrine metaplastic epithelium of cystic breast disease and breast cancer, but it is rarely found in normal breast epithelium. The refore GCDFP-15 detected in nipple aspirates of breast fluid (NAF) cou ld serve as a biochemical marker of the presence and possibly extent o f apocrine metaplasia within the breast.GCDFP-15 levels were measured in NAF from 37 Asian and 78 non-Asian women using radioimmunoassay. GC DFP-15 (range, 0-81,643 mug/ml) was found in the NAF of all but 1 woma n and was highly correlated between right and left breasts. Mean conce ntrations of GCDFP-15 were significantly lower in NAF from Asian compa red with non-Asian women. Markedly reduced levels of GCDFP-15 were fou nd in the 17 women who had been parous in the previous 2 years. In wom en not parous within the prior 2 years, no relationship was found betw een GCDFP-15 levels and age, weight, age at menarche, first-degree fam ily history of breast cancer, parity, oral contraceptive use, or smoki ng history. High concentrations of GCDFP-15 were found in the NAF of w omen with a history of a benign breast biopsy. Because similarly high levels of GCDFP-15 were found in NAF in over 40% of women without a hi story of benign breast biopsy, and because GCDFP-15 in the breast is p roduced only by apocrine metaplastic epithelium, we infer that the bre asts of these women likely contain a significant degree of apocrine me taplasia. Significantly higher concentrations of GCDFP-15 were found i n the NAF of Asian women with wet compared with dry cerumen. This prel iminary study supports the hypothesis that GCDFP-15 in NAF may be a us eful biomarker indicative of the presence of apocrine metaplasia in th e breast.