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Chemoprevention of Breast Cancer by Mimicking the Protective Effect of Early First Birth
Annual rept. 2 May 2008-1 May 2009
UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES
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We have successfully shown that in the rat estradiol, estradiol plus progesterone, and beta-HCG is protective against carcinogen-induced mammary tumorigenesis treatment and pregnancy induced RNA gene expression changes in the breast have been identified. Analysis of gene expression differences in the breast of parous and nulliparous women undergoing elective reduction mammoplasty has begun. Estrogen receptor, progesterone receptors and cell proliferation in the breast has been characterized by immunohistochemistry, IHC in parous and nulliparous women and in breast tissue obtained in the first trimester of pregnancy. RNA characterization of these samples has begun. Four protocols providing information related to chemoprevention have been developed - these investigate breast cell proliferation, receptor IHC and gene expression 1 the effect of high dose progestin exposure, recruitment ongoing 2 the effect of oral contraceptive progestin dose, recruitment complete, IHC being analyzed 3 the effect of high dose estrogen exposure, recruitment complete, IHC being analyzed and 4 the effect of natural progesterone exposure, recruitment complete. Pregnancy reduces mammographic density and breast cancer risk. How these are related has been studied in a large autopsy series results suggest that part of the protection may be the result of a reduction in breast epithelium further studies of these samples are ongoing.
APPROVED FOR PUBLIC RELEASE