Existing biomarkers and cancer prevention strategies are limited as the biology of breast tumor initiation remains poorly understood.
We aim to elucidate mammary epithelial cells that participate in tumorigenesis as a means of developing markers for risk stratification and targets for prevention. Important clues to the identity of these cells come from epidemiologic and our preliminary data. Early full-term pregnancy is one of the most effective protections against breast cancer in most women but not in BRCA1/2 mutation carriers. We investigated parity-associated variation in gene expression profiles of distinct cell types in normal breast tissues of nulliparous and parous women. The most significant differences were seen in CD44+ cells where many genes important in self-renewal and differentiation (e.g., p27, TGFB) were lower in parous women than in nulliparous and in parous BRCA1/2 mutation carriers. The numbers of p27+ and Ki67+ cells were also significantly lower in parous than in nulliparous women except in parous BRCA1/2 cases. The majority of p27+ cells were also estrogen receptor positive. In explant cultures of breast tissues, inhibition of TGFB increased proliferation with a concomitant decrease of p27+ cells implying that p27 due to TGFB is key for keeping breast epithelial progenitors in a quiescent state. Based on these preliminary data, we hypothesize that (1) a subset of p27+ and Ki67+ cells represent quiescent and proliferating hormone-responsive breast epithelial progenitors, respectively, (2) p27 and TGFJ3 play an important role in keeping these progenitors quiescent, (3) the number of these progenitors correlates with breast cancer risk, and (4) mechanisms regulating p27+ progenitors are perturbed in BRCA1/2 mutation carriers and this contributes to their high risk. To test these hypotheses we propose: 1. To characterize the molecular profiles of p27+ and Ki67+ human breast epithelial cells from normal breast tissue of women with different risk of breast cancer. 2. To investigate the role of p27 and signaling pathways that regulates its expression in human breast epithelial cell proliferation and differentiation. 3. To characterize the role of p27 in regulating the abundance of mammary epithelial progenitors and its effect of this on mammary tumorigenesis in animal models.

Public Health Relevance

The relationship between the number and characteristics of breast epithelial progenitors and breast cancer risk is an important but poorly studied area of research. The proposed project will investigate candidate regulators of human breast epithelial progenitors and their relevance for breast cancer risk, which may open new venues for improved risk prediction and chemoprevention.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Program Projects (P01)
Project #
Application #
Study Section
Special Emphasis Panel (ZCA1-RPRB-J (O1))
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Whitehead Institute for Biomedical Research
United States
Zip Code
Rashidian, Mohammad; Ingram, Jessica R; Dougan, Michael et al. (2017) Predicting the response to CTLA-4 blockade by longitudinal noninvasive monitoring of CD8 T cells. J Exp Med 214:2243-2255
Dreijerink, Koen M A; Timmers, H T Marc; Brown, Myles (2017) Twenty years of menin: emerging opportunities for restoration of transcriptional regulation in MEN1. Endocr Relat Cancer 24:T135-T145
Hydbring, Per; Wang, Yinan; Fassl, Anne et al. (2017) Cell-Cycle-Targeting MicroRNAs as Therapeutic Tools against Refractory Cancers. Cancer Cell 31:576-590.e8
Bierie, Brian; Pierce, Sarah E; Kroeger, Cornelia et al. (2017) Integrin-?4 identifies cancer stem cell-enriched populations of partially mesenchymal carcinoma cells. Proc Natl Acad Sci U S A 114:E2337-E2346
Wang, Yu; Woehrstein, Johannes B; Donoghue, Noah et al. (2017) Rapid Sequential in Situ Multiplexing with DNA Exchange Imaging in Neuronal Cells and Tissues. Nano Lett 17:6131-6139
Dongre, Anushka; Rashidian, Mohammad; Reinhardt, Ferenc et al. (2017) Epithelial-to-Mesenchymal Transition Contributes to Immunosuppression in Breast Carcinomas. Cancer Res 77:3982-3989
Dreijerink, Koen M A; Groner, Anna C; Vos, Erica S M et al. (2017) Enhancer-Mediated Oncogenic Function of the Menin Tumor Suppressor in Breast Cancer. Cell Rep 18:2359-2372
Wang, Haizhen; Nicolay, Brandon N; Chick, Joel M et al. (2017) The metabolic function of cyclin D3-CDK6 kinase in cancer cell survival. Nature 546:426-430
Hydbring, Per; Wang, Yinan; Bogorad, Roman L et al. (2017) Identification of cell cycle-targeting microRNAs through genome-wide screens. Cell Cycle 16:2241-2248
Tavera-Mendoza, Luz E; Westerling, Thomas; Libby, Eric et al. (2017) Vitamin D receptor regulates autophagy in the normal mammary gland and in luminal breast cancer cells. Proc Natl Acad Sci U S A 114:E2186-E2194

Showing the most recent 10 out of 127 publications