Luminal progenitor cells in women with BRCA1 mutations have 'forgotten' how to behave, Dr Lindeman said. "Usually, luminal progenitor cells multiply rapidly in the presence of certain growth factors. In BRCA1 women these cells don't even require growth factors to proliferate they misbehave from the outset.
"We also know that the BRCA1 gene is required for normal DNA repair. There may therefore be a triple whammy effect faulty growth control, faulty DNA repair and expanded luminal progenitor cell numbers ultimately resulting in breast cancer in some BRCA1 mutation carriers."
Dr Visvader said in the long-term, breast biopsies might be able to reveal misbehaving luminal progenitor cells. What's more, certain 'markers' might one day help guide diagnosis and treatment. "For example, c-KIT is a key marker of the luminal progenitor cell and I expect we will see an increase in pathologists routinely using this as a diagnostic marker for basal-like tumours," she said. "It may even be possible to develop new drugs that target c-KIT, since drugs are already available that target different forms of this marker."
Dr Lindeman said the identification of stem cells, luminal progenitor cells and other cell types in the breast was now beginning to reveal a breast cancer roadmap - highlighting cancer-prone cell types and key genetic pathways. "Hopefully this will lead to new, tailored therapies for the next generation of women."
Dr Visvader said the research had only been possible through the generous donation of breast tissue by women undergoing breast surgery, together with the support of their surgeons and pathologists. The study was facilitated by the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer.
|Contact: Penny Fannin|
Walter and Eliza Hall Institute