IMAGE: The epigenetic regulatory protein DNA methyltransferase 1 (green) is highly expressed in the luminal cells of mammary gland ducts (compared with basal cells, red). Treatment with the inhibitor decitabine (right)… view more
Researchers at the Princess Margaret Cancer Centre in Toronto have discovered that epigenetic proteins promote the proliferation of mammary gland stem cells in response to the sex hormone progesterone. The study, which will be published June 19 in the Journal of Cell Biology, suggests that inhibiting these proteins with drugs could prevent the development of breast cancer in women at high risk of the disease.
Mammary glands contain two types of cells, basal and luminal, that arise from specialized stem or progenitor cells. During pregnancy or the menstrual cycle, progesterone induces basal and luminal progenitor cell numbers to expand and drive mammary gland formation. But mammary gland progenitors may also give rise to cancer. Progesterone exposure and stem cell proliferation have been linked to the development of breast cancer, and the number of progenitor cells is often elevated in women carrying mutations in BRCA1 or other genes that put them at a high risk of developing the disease.
“Currently, there are no standard of care preventative interventions
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