Abstract
Serum levels of YKLโ40 have been associated with inflammatory diseases and breast cancer. Our purpose was to determine if YKLโ40 in breast tissue, nipple aspirate fluid (NAF) and serum is (i) concentrated in NAF compared to matched serum, (ii) increased in the NAF, serum or tissue of women with biopsy proven precancer or cancer compared to healthy women and (iii) influenced by menopausal status. 118 women (61 healthy subjects, 10 with precancer and 47 with breast cancer) aged 17โ95 years provided NAF with or without serum samples for analysis. Matched tissue was analyzed from a subset of subjects who underwent breast biopsy. All NAF and serum samples had detectable levels of YKLโ40. Median YKLโ40 levels for the entire cohort were 683 fold higher in NAF than serum. Premenopausal subjects had higher NAF and lower serum levels of YKLโ40 than postmenopausal subjects. YKLโ40 levels in NAF but not serum were higher in women with precancer (atypical hyperplasia and lobular carcinoma in situ) than in either healthy subjects (p = 0.025) or subjects with breast cancer (p = 0.015). In women with precancer, YKLโ40 distribution in tissue correlated with YKL serum level (p = 0.043). YKLโ40 is concentrated in NAF, with the highest concentrations in premenopausal women. NAF levels of YKLโ40 are significantly higher in women with precancers than healthy subjects, suggesting that measuring YKLโ40 in NAF may improve the identification of women at increased breast cancer risk. ยฉ 2007 WileyโLiss, Inc.