The study, published today in the journal Cell Stem Cell, shows for the first time that the most aggressive and hard-to-treat types of the disease are likely to arise from intermediary, or progenitor, cells. The results run counter to the commonly-held theory that breast cancer originates in stem cells. This is hugely significant in directing future research into combating the disease.
Study leader Dr Matt Smalley, from the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research (ICR) in London, said: “These results represent a major advance in our understanding of breast cancer. It means we can now look very closely at where the disease forms and which genes are involved in that process. This knowledge will greatly improve the chance of finding effective new targeted treatments for breast cancer patients in the future.”
The team attempted to replicate inherited forms of human breast cancer in mice by giving them a faulty BRCA gene, which is known to cause the disease. They introduced the defect into the stem cells of one group of mice and into the intermediary cells of a separate group. The cancers which developed from stem cells did not resemble inherited breast cancer.
Strikingly, the cancers that formed from intermediary cells were almost identical to triple negative breast cancer and forms of the disease which run in the family. The authors therefore concluded that these types of breast cancer form in intermediary cells.
Triple negative breast cancer and breast cancer caused by faulty BRCA genes are two of the most aggressive types of the disease. They represent about 8,000 of the nearly 46,000 breast cancer cases in the UK each year. There is currently no targeted treatment for triple negative breast cancer, which is more common in younger women and black women. A targeted treatment for inherited forms of breast cancer, called PARP inhibitors, is currently showing promise in clinical trials.
Professor Alan Ashworth, Director of the Breakthrough Breast Cancer Research Centre at the ICR, said: “Understanding the biology of breast cancer is essential for the future development of new ways to treat and prevent the disease. Our research gives a considerable new insight into how the disease forms and grows.”
Media Contact: Richard Purnell in the Breakthrough Breast Cancer press office on 020 7025 0290
Notes to editors:
Stem cells, intermediary (progenitor) cells and normal, functional cells
Adult stem cells are long-lived cells which can divide many times. In adult organs they are responsible for replacing normal functional cells as they become worn out.
The majority of cells in the human body are limited by the number of times they can divide. They are usually fixed, so that they only carry out particular functions, such as producing milk in the breast. Normal functional cells develop from stem cells through a series of intermediary (or progenitor) cells.
Due to the fact that stem cells are long-lived and have the potential to divide many times it has been proposed that they are the origins of many types of cancer. It has also been suggested that they may play a role in the development of resistance to treatments by cancers.
About breast cancer
- Breast cancer is the most commonly diagnosed cancer in the UK – nearly 46,000 women and around 300 men are diagnosed every year.
- Breast cancer accounts for nearly 1 in 3 of all female cancers and one in nine women in the UK will develop breast cancer at some point in their lifetime.
- More than 1,000 women die of breast cancer every month in the UK.
- The good news is that more women than ever in the UK are surviving breast cancer thanks to better awareness, better treatments and better screening.
About Breakthrough Breast Cancer
- Breakthrough Breast Cancer is a pioneering charity dedicated to the prevention, treatment and ultimate eradication of breast cancer. The charity fights on three fronts: research, campaigning and education.
- Breakthrough Breast Cancer funds ground-breaking research, campaign for better services and treatments and raise awareness of breast cancer. Through this work the charity believes passionately that breast cancer can be beaten and the fear of the disease removed for good.
Find more information at www.breakthrough.org.uk
About The Institute of Cancer Research (ICR)
- The ICR is Europe’s leading cancer research centre
- The ICR has been ranked the UK’s top academic research centre, based on the results of the Higher Education Funding Council’s Research Assessment Exercise
- The ICR works closely with partner The Royal Marsden NHS Foundation Trust to ensure patients immediately benefit from new research. Together the two organisations form the largest comprehensive cancer centre in Europe
- The ICR has charitable status and relies on voluntary income, spending 90 pence in every pound of total income directly on research
- As a college of the University of London, the ICR also provides postgraduate higher education of international distinction
- Over its 100-year history, the ICR’s achievements include identifying the potential link between smoking and lung cancer which was subsequently confirmed, discovering that DNA damage is the basic cause of cancer and isolating more cancer-related genes than any other organisation in the world
For more information visit www.icr.ac.uk