PMH cancer researchers link ovarian hormone to breast stem cells growth

May 05, 2010

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, are significant because reproductive history is among the strongest risk factors for , 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 .

"Our study shows how and when hormones affect breast stem cells during the natural . There are well accepted links between ovarian hormones and breast cancer, and there is mounting evidence that stem cells are seeds for breast cancer. We now show a direct connection between hormones and breast stem cells. "

Lead author Purna Joshi adds: "Our research demonstrates that when progesterone peaks during the second half of the menstrual cycle, it starts a cross-talk between stem cells and neighbouring cells that propels normal breast stem cells to expand in number, and may trigger an environment where cancer can begin."

Until now, breast stem cells were thought to be generally inactive in the adult female breast, says Dr. Khokha, whose speciality is modelling human cancer in the laboratory. In this study, the research team replicated the human natural reproductive cycle in mice to determine the impact of hormones on breast stem cells.

How hormones change these stem cells opens a new pathway to understanding the cell growth that begins breast cancer, and, with further research, will open new ways of targeting .

"It is the first evidence, to our knowledge, for progesterone-driven dynamic shifts in the mammary stem cell pool. This activation provides an opportunity to start the process of cell transformation leading to breast cancer."

Explore further: Chronic inflammation linked to 'high-grade' prostate cancer

More information: DOI:10.1038/nature09091

Provided by University Health Network

not rated yet

Related Stories

Therapy may block expansion of breast cancer cells

Nov 05, 2008

Breast cancer stem cells are known to be involved in therapy resistance and the recurrence of cancerous tumors. A new study appearing in Clinical and Translational Science shows the mechanisms governing stem cell expansion in bre ...

Herceptin targets breast cancer stem cells

Jul 09, 2008

A gene that is overexpressed in 20 percent of breast cancers increases the number of cancer stem cells, the cells that fuel a tumor's growth and spread, according to a new study from the University of Michigan Comprehensive ...

Broccoli component limits breast cancer stem cells

May 03, 2010

A compound derived from broccoli could help prevent or treat breast cancer by targeting cancer stem cells -- the small number of cells that fuel a tumor's growth -- according to a new study from researchers at the University ...

Recommended for you

Unraveling the 'black ribbon' around lung cancer

Apr 17, 2014

It's not uncommon these days to find a colored ribbon representing a disease. A pink ribbon is well known to signify breast cancer. But what color ribbon does one think of with lung cancer?

User comments : 0

More news stories

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.