Accession Number : ADA516520


Title :   Chemoprevention of Breast Cancer by Mimicking the Protective Effect of Early First Birth


Descriptive Note : Annual rept. 2 May 2008-1 May 2009


Corporate Author : UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES


Personal Author(s) : Pike, Malcolm C


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a516520.pdf


Report Date : Jun 2009


Pagination or Media Count : 53


Abstract : 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.


Descriptors :   *BREAST CANCER , CONTRACEPTION , TISSUES(BIOLOGY) , DOSAGE , GENES , CARCINOGENS , PREGNANCY , CELLS(BIOLOGY) , RIBONUCLEIC ACIDS , RECEPTOR SITES(PHYSIOLOGY) , ORAL INTAKE , AUTOPSY , MAMMARY GLANDS , IMMUNOCHEMISTRY , HISTOCHEMISTRY , PROGESTERONE , PLASTIC SURGERY , EPITHELIUM , HORMONES


Subject Categories : Anatomy and Physiology
      Medicine and Medical Research


Distribution Statement : APPROVED FOR PUBLIC RELEASE