Breast density affects mammographic sensitivity and is predictive of breast cancer risk. Factors that increase breast density may compromise the reduction in mortality gained by mammographic screening. Understanding these factors is crucial as it may help us improve mammographic screening and reduce breast cancer risk. Prolactin, an endogenous hormone that acts as a mitogen and differentiating agent in the breast, may be one such factor. To our knowledge, this is the first study to examine the association between prolactin and mammographic breast density in a cross-sectional study of healthy, cancer-free postmenopausal women.
A weak, but statistically significant correlation was observed between prolactin and percent breast density (spearman correlation coefficient of 0.1197; p-value 0.013) after adjusting for every being pregnant and ever breast feeding. Prolactin is most likely one of several factors that contribute to increased mammographic breast density, and further analyses are needed to determine its full contribution. No statistically significant associations were observed for the prolactin gene single nucleotide polymorphisms (SNPs) examined in relation to prolactin, percent breast density, or proportion of dense breast area. However, two SNPs in the prolactin receptor gene (rs7734558 and rs7705216) were significantly associated with serum prolactin level at the 0.10 significance level. Women with the G allele (AG and GG) at SNP rs7734558 have a slightly elevated level of prolactin when compared with women homozygous for the A allele (AG 10.76 ± 6.40 ng/mL, GG 10.77 ± 4.60 ng/mL vs. AA 9.86 ± 6.32 ng/mL); and those with the GG allele at SNP rs7705216 have a slightly elevated prolactin level when compared with individuals with the C allele (GG 11.71 ± 2.78 ng/mL vs. CG 11.15 ± 6.22 ng/mL, CC 10.27 ± 5.99 ng/mL). These SNPs need to be further investigated to determine their full contribution in relation to serum prolactin levels.
Having an understanding of factors that affect breast density is an important public health issue has it may lead to improvements in breast cancer screening and help identify not only women at an increased risk for breast cancer, but women who may benefit from prevention strategies.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04082009-171000 |
| Date | 29 June 2009 |
| Creators | Leiras, Claudia Costa |
| Contributors | John W. Wilson, M. Michael Barmada, Anthony J. Zeleznik, Jane A. Cauley, Joel L. Weissfeld |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-04082009-171000/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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