PMH breast cancer researchers link ovarian hormone to breast stem cells growth

Note: easier to read Medscape article from previous blog post

"Cancer researchers at Princess Margaret Hospital (PMH) have discovered that the ovarian hormone progesterone plays a pivotal role in altering breast stem cells, a finding that has important implications for breast cancer risk.......The findings, published online today in Nature (10.1038/nature09091; http://dx.doi.org/), are significant because reproductive history is among the strongest risk factors for breast cancer, says principal investigator Rama Khokha, a molecular biologist at Ontario Cancer Institute and the Campbell Family Cancer Research Institute, PMH. Other major known risk factors are age, genetics and breast density."